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Section - 22. What is the Microbiology of San Francisco Sourdough?

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Several studies have been conducted on the natural microbiological
flora of sourdoughs from around the world.  In terms of understanding
the basis of the symbiosis between yeast and lactobacilli the most
successful studies have been by Sugihara and colleagues.  Despite the
existence of several varieties of yeast and lactobacilli they showed
that the dominant yeast was a non spore forming variety of
Saccharomyces exigus called Torulopsis holmii and now reclassified as
Candida milleri sp. nov.  The dominant lactobacillus was a new
species christened Lactobacillus sanfrancisco sp. nov.

Yeast and bacteria occur in a ratio of 1:100.  The unique symbiosis
is explained thus: Though most strains of yeast can metabolise the
sugar maltose Candida milleri cannot.  Dough abounds in maltose which
is a released from "damaged starch" through the action of amylase
enzymes. Thus maltose is freely available to the lactobacilli which
have an absolute requirement for this sugar and they cannot utilise
other sugars present in dough.  The yeast can utilise all other
sugars present in dough thus the two critters do not compete for a
carbon source.  In addition, the lactobacilli have an enzyme maltose
phosphorylase which while assimilating maltose releases glucose into
the media to give the yeast a small boost.

The lactobacilli also secrete an antibiotic cycloheximide which
"sterilises" the dough since it kills many organisms but of course
Candida milleri is resistant to cycloheximide.

Lastly, Candida milleri is moderately tolerant to the acetic acid
which the lactobacilli produce. I should also note that the
nutritional requirements of the lactobacilli is complex - they
require a number of amino acids and fatty acids which may be derived
from dead yeast cells.

Spicher in Germany characterised German sour rye. He found the
dominant yeast species were Candida krusei, Saccharomyces cerevisiae,
Pichia saitoi and Candida milleri.  The Lactobacilli included L.
brevis, casei, fermenti, pastorianus, bucheneri, delbrueckii,
leichmannii, acidophilus, farciminis, alimentarius, brevis
var.lindneri, fermentum, fructivorans and Pediococcus acidilactici!
(This zoo of organisms present naturally in Rye flour is the reason
why it is so easy to start a good sourdough culture from rye for
example see "manuels starter" in the Laurel's Kitchen bread book.)

Pure culture studies showed that he could reconstitute a starter that
was close to the original with the yeast Candida krusei and
Lactobacillus brevis var. lindneri. The basis of the symbiosis is not
well understood to the best of my knowledge but is probably similar
in principle to the one described above for San Francisco sourdough.

On a final note, I should point out that pure cultures of
Lactobacillus sanfrancisco are grown on defined media, harvested and
freeze dried and supplied to bakeries around the world to make
instant sourdough!

Should there be sufficient interest in this sort of information, I
can post periodic updates on the scientific lore of breadmaking.



 Subject: 23. What about Ed Wood's latest edition of his book?

Ed Wood's new edition of his authoritative book on sourdough,(World
Sourdoughs From Antiquity, Ed Wood, 1996, ISBN 0-89815-843-5, Ten
Speed Press, $16.95 paperbound, approximately 9" x 7") is an
attractive book, well laid out, with 185 pages and 8 pages of colour
photos. Some of the colour photos could be helpful to the novice in
learning some of the techniques of bread making. Other colour photos
are from the National Geographic project on ancient sourdough and are
interesting for their historical content.

The book opens with Ed's experiences in investigating with others on
a team how man made his first leavened bread in Egypt, a project
supported by the National Geographic. These experiences and
discoveries were the subject of an article in National Geographic in

Ed continues with an expert and thorough introduction to sourdough
cultures, their care and feeding, theory, and of course, the making
and baking of sourdough bread.

The book has a good index and around 120 pages of a wide variety of
interesting sourdough recipes, roughly one recipe per page, of
standard and exotic breads, together with pancake and waffle recipes.
This makes for a good book to have on hand both for the novice
learning and the experienced sourdough hand looking for something

There is also a chapter on baking sourdough in bread machines.
However, I agree with Ed that making sourdough in bread machines
involves more art than science. No bread machine on the market that I
know of is really designed for sourdough.

Ed's company, Sourdoughs International, which sells sourdough
cultures, is on the web, and contact information is at



 Subject: 24. How can I start a starter from scratch?

I'm puzzled why starting a starter presents a problem to many people.
It really is an extremely simple procedure. I often forget to hold
back some starter from a dough, so I wind up baking the whole lot and
I'm left with no starter to continue, and I have to regenerate from
scratch again. This is an inconvenience, not a disaster! Perhaps I'm
a little careless here, partly because it's so easy to do. In the
hope that it might be helpful to others, here are my thoughts on the

-       Firstly, forget everything you ever heard about catching
yeasts "from the air." Yes, there _are_ yeasts - and lactobacilli -
in the air, but from a practical point of view it is important to
note that there are far more of them already present in flour!  In a
cup of flour we're talking millions of them. So the good news is that
you already have the yeasts and bacteria you need, right off the
supermarket shelf, the bad news is that you also have mold spores and
other bacteria which aren't so desirable. Fortunately, given the
right conditions the yeasts and lactobacilli quickly dominate and the
starter becomes too acidic for the other organisms to survive. The
microorganisms are not destroyed (though they are probably
diminished) by bleaching so can happily get a starter going from
normal store flour. However, since they are more plentiful on the
surface of the grain, a wholemeal flour is the easiest (quickest) to
get going.

-       Remember that the sourdough microflora require food, moisture
and the correct temperature. You provide food from flour. Rye flour,
because it contains more sugars than wheat, provides more quickly
available food, so for this reason it is easier (i.e. quicker) to get
a sour going. Also, whole grain flour contains more proteolytic
enzyme and amylase (which exist in higher quantities just under the
surface of the grain), so again the food source is richer and the
sour is quicker to get going. The most important point to remember is
to feed regularly.  For a beginning starter you need to feed every 24
hours. At the first feed, you probably will not notice much or any
activity, except perhaps a slightly winey aroma (especially if you
use rye). Never mind: feed anyhow. I suspect this is where most
people go wrong - figuring that leaving it a few more days will get
it going! In reality, the yeasts are running out of readily available
food so they are less active, while the molds and other 'off'
bacteria continue to multiply, so you wind up with a slimy goo. By
the second or third feed the starter will be bubbling nicely. By the
fourth or fifth feed it will be adequate to bake with, but it will
continue to develop for a few more days.

-     Temperature should be 70-80F ( 20 - 25C ). You could go warmer
than this, but you would then need to feed more often; also, the
nature of your sour would be different, less desirable for a good

-      Moisture comes from water which you add with the flour. I use
50/50 by weight, which by volume is approximately 1/2 cup water per
cup flour. You don't need to be too precise, so volumetric
measurement is fine, and simple. You can use a more liquid starter,
but you will have to feed more often. [I've seen various discussions
about tap vs bottled water, and tap water works just fine. I suppose
if you live somewhere that has outrageously high chlorination it
might be different, but in general if you choose bottled water you do
so for your own health, not the health of the starter!]

To put it all together: Take 1/2 cup flour (preferably whole meal
rye), mix to paste with 1/4 cup water in a 1 cup size container.
Cover and leave for 24 hours at 70 - 80F. Throw away half of the
mixture, and refresh with another 1/2 cup flour and 1/4 cup water,
cover and leave for 24 hours as before. Repeat. By now, the starter
should show bubbles. If using rye, start using regular white flour
after the third or fourth feed. Now you have a starter which you keep
alive indefinitely by regular feeding.

Happy baking.


Date: Thu, 3 Aug 2000

I was just looking at your article about sour starters. Lots of hard to f=
Info. Just one thing I would like to add is the use of organic flours. Go=
Medal has an organic white flour in most of the stores around here, Portl=
Oregon. Try mixing 2 cups of this flour with 2 cups filtered water. This =
of year the starter can used in about 8 hours, or less. It's almost



 Subject: 25. How do I get holey, sour, moist and long keeping bread?

I get the most moist dough and most irregular holes when I have the
most over mature dough.  Unfortunately, this also correlates with
lower loaf volume and more slump.  However, if you look at the loaves
pictured in French Specialty and Decorative Breads (or whatever the
title is, I've lent out my copy), you will see that the bread
fermented with old dough is like that - fairly flat round loaves, and
that wonderful texture I seem to get most often when something goes

As far as allowing the dough to "proof" (I'd use the term ferment, or
rise) for a few hours before shaping, that is my standard operating
procedure.  I usually let it at least double twice (punching down in

So, in general, if I always go to the next stage (starter to sponge
to dough to loaf) when that stage is at maximum volume, I get less
sour bread with more "conventional" texture.  The more I let the
stages go, especially the dough stage, the more holey, sour, moist
and long keeping the bread is.

- Jeff

An irregular crumb is achieved with an extensible dough. This is most
easily done using a "weak" flour. French bread flour (type 55) has a
protein level which is extremely low by US standards (9 - 10 %  vs
12%+). Using a weaker flour, highish hydration (65%+) and short
mixing time is the surest way to get good irregular crumb, and don't
shape your loaves too tightly. But don't expect enormous holes, as in
ciabatta, unless you to extreme hydration. Of course, the lower
protein flour will have less tolerance than a normal US bread flour,
so be careful not to overproof.

- Jonathan


 Subject: 26. Is slashing of loaves aesthetic or functional?


Historically, French rural ovens were communal, in a sense: they were
originally owned by the lord, and maintained by a fournier, or
ovenmaster, who kept the oven hot but charged for its use.  Since the
bread of each household would be mixed with others in the oven, a
distinctive slash was one way to tell the loaves apart. After the
feudal power of other lords (and the Church, which also controlled
many ovens) was broken, the ovens were (and are, in places like
Bugey, in Eastern France) owned by the "commune", the governmental
body of the city or district. The are still used on holidays, and the
bread is still distinctively slashed.

Anyway, bread which is not baked in a pan and which is not proofed in
a 100% humidity environment will almost always burst as it is baked,
and the burst is uncontrolled and messy.  The slash controls this,
but is also decorative - it enhances the vitality of the process...
as the burst shows how well the baker matched the rising power of the
leaven to the mechanical properties of the gluten. A nice slash and
shred is a sign of proficiency in baking.

Whole grain breads that do not rise or spring as markedly do not need
to be slashed if they are proofed in a high-humidity environment.


Additionally slashing prevents a "flying crust." Flying crust is a
term describing the lifting of the entire upper crust of a loaf
during baking to form one large bubble.



 Subject: 27. How do lactic bacteria affect sourdough bread?

13 Feb 1997 10:49:32 +0100

Dear Daniel Wing!

Your letter to Prof. Hammes has reached Hohenheim, and Prof. Hammes
has asked me to take care of the communication. I am a Ph.D.
candidate in Hammes' lab working on the physiology of sour dough

Please feel welcome to address questions to us concerning sour dough
microbiology and technology! I will mail two recent publications or
our lab concerning the physiology of sour dough lactic acid bacteria
by mail, but as they may take a week or longer to reach you, I will
give a few comments on the questions in your letter:

- yeasts do not produce appreciable amounts of either lactic or
acetic acids, their main metabolites are ethanol and CO2. If
acidification of the dough is desired or required (e.g. if rye flour
is used), lactic acid bacteria or organic acids (most commonly lactic
or citric acids) are added.

- homefermentative lactic acid bacteria do produce solely lactic acid
from maltose or glucose under anaerobic conditions (as they are
prevailing in sour dough fermentations). Thus, doughs acidified with
homofermentative lactic acid bacteria (LAB) contain but little acetic
acid. As homofermentative lactic acid bacteria do not produce CO2,
yeast must be added to ensure leavening of the dough.

- In sour doughs with a tradition of continuous propagation (such as
the San Francisco French Bread Sour Dough process, German rye sour
doughs or sour dough employed in Pannettone production in Italy),
heterofermentative lactobacilli, especially L. sanfrancisco, are
dominating the fermentation. Heterofermentative lactobacilli produce
lactate, ethanol, and CO2 from hexoses (most strains do not ferment
pentoses), HOWEVER, if additional substrates are present that serve
as electron acceptor to balance, acetate is produced instead of
ethanol. I do not know whether or not you are familiar with the
concept of the  "redox balance": Degradation of hexoses via the
pentose-phosphate pathway as employed by heterofermentative LAB
results in phosphorylation of ADP to ATP, and in the reduction of NAD
to NADH. As there is no use for NADH, it must be oxidized to NAD
again. In the absence of other substrates, acetyl-Phosphate is
reduced to ethanol, with two NADH becoming oxidized to HAD in the
process. If either fructose, oxygen, citrate or malate are present,
these become reduced to mannitol, H2O, lactic and acetic acid, and
succinate, respectively, and acetyl-P is dephosphorylated to acetate.
(This explanation may not be very straightforward, I hope we did a
better job in the publications I`m about to send you; these also
include a diagram showing the metabolic pathways of L. sanfrancisco).
The consequence for the molar ration of lactate:acetate (fermentation
quotient, FQ) in sour dough fermentations is, that acetate in
produced only if one or more of the above mentioned co-substrated is
present. Oxygen is present only in the beginning of the fermentation,
and the amounts of oxygen are too low to result in significant
amounts of acetic acid, though, in principle, it is possible to
increase the acetate content by aeration of dough. Fructose is
present in sucrose and other glucofructans with higher molecular
weights. Fructose is released from these compounds by cereal or dough
enzymes (many strains of L. sanfrancisco don`t even cleave sucrose)
and consequently reduced to mannitol by L. sanfrancisco. The ration
of mannitol : acetate in sour dough fermentation is approximately
2:1, suggesting that fructose is the most important electron
acceptor. Furthermore, citrate and malate are present in the dough in
amounts less than 10 mmol/kg, these are utilized also.

Thus, the effect of substrates and oxygen on the FQ is nicely
explained by the metabolic characteristics of the dominating
fermentation organisms. Dough yield (=3Dkg dough per 100 kg flour) and
temperature also influence the FQ. Spicher reports that softer doughs
lead to an increased FQ; an increase in temperature results in higher
amounts of lactic acid, while the amount of acetic acid remains more
or less the same, thus, the FQ is increased again. I do not have a
straightforward explanation for these phenomena, but changes in dough
yield and temperature will result in changes in buffering capacities
of the dough, modified activities of cereal and microbial enzymes, as
well as a changed ration of yeasts : lactobacilli counts, all of
which are likely to influence the FQ.


Michael Ganzle


Dear Michael Gaenzele

Thank you for sending one of the most gracious letters I have ever
received in response to any kind of an inquiry. Since I wrote to
Prof. Hammes I have been able to copy a number of articles from
English language publications by Drs. Brummer, Spicher, Vogel, and so
forth. Unfortunately, some of them have been in non-technical
journals and were thus short on details, and even the less technical
ones were not as clearly and idiomatically written as your letter. I
DID have a hard time understanding what was meant by Dough Yield, for
instance, although I had figured it out before I got your letter. I
am still not sure I understand some of the statements those authors
made about the acid content of doughs (such as the units of
measurement), but I have been piecing things together by looking at
all the articles cumulatively. Your letter has clarified a great
deal. I will put stars next to my current questions to make THIS
letter easier to answer. Like this *.

One problem for me was that I did not realize how predominant rye
flours were in German sourdough baking. I know that typical rye
pentose is about 8% and that pentose viscosity is important in
gas-trapping in rye doughs (He and Hoseney, 1991) but I still don't
know how an acidified rye dough behaves differently from a more
neutral one. *Does it affect viscosity somehow? He and Hoseney
studied neutral doughs only.

I also do not understand why Brummer says "Anstellgut" is a
non-translatable term. *What do you think it translates as? *I take
it that this a very ripe starter, very acid, maintained at room
temperature at some infrequent rate of refreshment? *Is it always rye
based? *Always a high-ash flour? *How is it different from the type
of French and American wheat starters that are refreshed 1:1 every
eight hours, or 1:4 every 12 hours? *What is its consistency, pH,
Total Titratable Acid? *My assumption is that my lack of
understanding comes from the German use of sourdough as primarily
acidification, whereas here we look for a little acidification, a
good flavor, and good leavening power.*Do German bakers ever make
wheat breads leavened with higher starter percentages than those
Brummer cites, for example 20% or 30% starter? *Or do they acidify
with very ripe starters and leaven with commercial yeast?

I am curious about the flavor/sensory aspects of the FQ: *When a
bread is fairly sour (SF Sourdough, some rye breads) is the perceived
sourness mostly lactate, mostly acetate, or due to the pH or TTA of
the bread? Calvel brings this subject up, but does not resolve it to
my understanding.

As for your answers to my previous questions, thank you -- I will
look this material over again, and let you know if I have questions.
*Do you mind if I put the text of your letter (with attribution) on
the internet as a posting to the newsgroup Rec.Food.Sourdough? I will
NOT put your address or email address in the posting, unless you want
me to. Please let me know, as I think it might become part of the FAQ
file there (Frequently Asked Questions). I will forward your entire
letter to a very few people in academia here who have been helping
me, so you might hear from one of them.

Dan Wing


14 Feb 1997 15:50:30 +0100

Dear Dan Wing!

I do not mind if the answer is posted to the I've
also been browsing in that newsgroup.

To answer a few of your questions:

I) There is no rye bread without acidification of the dough. Rye
flour does not contain gluten (or a different type of gluten that
does not have the gas-retaining properties), so that the structure of
rye bread relies mainly on gelatinized starch. Rye flour does have a
higher amylase activity than wheat flour, furthermore, the
gelatinization temperature is a few degrees lower than that of wheat
starch. Thus, with the temperature optimum of rye amylase being about
50 - 52C (with substantial activity up to temperatures of 70C) and
starch gelatinization starting at 55C, starch is degraded during the
baking process UNLESS the amylases are inactivated by lowering the pH
below 4.5. The situation is exacerbated if there was wet weather
during the harvest, as germinating rye has higher amylase activities
and the starch granules are damaged, thus facilitating hydrolysis.

II) "Anstellgut" is more or less the same as the continuously
propagated wheat starters of the SF sour dough bread, so no harm is
done if it is translated as "starter sponge" or something like.
German sourdoughs usually are rye based for two reasons: 1) Due to
the climatic conditions in Germany, especially in the northern and
eastern parts that make it difficult to grow wheat, rye flour is just
as important for bread production as wheat flour. 2) As these is no
necessity to acidify wheat flour (though it enhances the flavor),
most bakers do not use sour dough to produce  wheat bread. Starter
sponges are not necessarily propagated separately. If the dough is
taken care of according to traditional methods, it is re-inoculated
three times to produce bread dough (reading Bruemmer and Spicher, you
probably have already encountered the "three stage sour dough
method." A part of the bread dough is used to prepare the sour dough
for the next day. This makes 3 - 4 inoculations a day, the ratio of
sour dough to fresh dough being approximately 1:3. One has to make a
point of it: there is no typical sourdough without continuous
propagation! The microflora of these rye starters is actually the
same as for wheat starter in SF or Italy: Lactobacillus sanfrancisco
and Candida milleri or Saccharomyces exiguus. The pH of a ripe sour
dough will be between 3.6 and 4.0 (L. sanfrancisco does not grow
below pH 3.6). The total titrable acidity (TTA) depends on the flour
employed: as the lactobacilli acidify to pH 3.6, flours with high
buffering capacity (amount of acid required to lower the pH), e.g.
whole flours, have a higher TTA than white flours with a low
buffering capacity. Furthermore, if "hard" water with high
concentrations of Me2+ CO3- is used, the TTA will be higher.

3) Acidification vs. leavening: As mentioned above, rye flour or
mixtures of rye and wheat flours containing more than 20% rye must be
acidified in order to get bread. As the propagation of sour dough is
very time consuming if the full leavening capacity of the organism is
to be obtained, quite a few processes have been developed in Germany
that ensure that the dough is acidified (or that the sour dough added
to the bread dough contains enough acid to bring the pH of the bread
dough below ca. 4.5), but no leavened by the sour dough microflora.
Leavening is achieved by bakers yeast. Basically, there are three
possibilities: 1) Dried sourdough with a high TTA (>20) is added to
the bread dough, there are no lactobacilli involved in the
fermentation (sometimes they are present in the dried sour dough
preparation anyway, as in Germany, something called sour dough must
contain viable lactic acid bacteria. The dried dough is sold much
more readily if it can be called sourdough). 2) A sour dough is kept
at room temperature for up to one week. The TTY of that dough is high
enough to use it for baking, but as the organisms are rather stressed
in such an environment, they will not contribute to the leavening of
the dough. Such doughs do not contain lactobacillus sanfrancisco, but
other lactobacilli that are more acid tolerant (the ph of such a
dough reaches 3.4 - 3.6 after one day, and stays there for the four
or five more days that the dough is kept).  3) One stage or two stage
processes with starter sponges. One or two stage processes usually do
not ensure that the lactobacilli in the dough are fully metabolically
active if the bread dough is prepared, thus, the leavening capacity
is rather poor, but enough acid has been produced. As far as I know
(I never made a survey, though), only few bakers make bread with
traditional processes without bakers yeast added to leaven the dough.
Acidification of the bread dough with sour dough is rather common,
and the sensory quality of such bread is quite close to that of bread
made without bakers yeast. Straight processes with bakers yeast and
chemical acidification (citric, lactic, and acetic acid, or mixtures
thereof) are also quite common to produce rye bread.

4) Lactic acid and acetic acid will change taste and flavor of bread
beyond the decrease of pH: the taste buds (sour, bitter, sweet,
salty) are on the tongue, any other aroma is perceived with the nose;
therefore, the aroma compounds must be volatile. Acetic acid is more
volatile than lactic acid, thus, it's impact on the flavor is more
pronounced than that of lactic acid. Spicher says that a ratio of 20
acetate to 80 lactate is optimal. It must also be taken into account,
that the lowering of the pH influences the formation of other aroma
compounds during the baking process. The acetic acid is furthermore
important as growth of spoilage organisms such as molds or rope
causing bacilli (Bacillus subtilis) is inhibited by high acetic acid

I hope that I could answer your questions

With kind regards

Michael Ganzle


 Subject: 28. What is hooch? Refrigerator hooch? What do I do with it?

Hooch and refrigerator hooch are the same thing.

When the starter goes quiet (this tends to happen faster in the
refrigerator, whence 'refrigerator hooch') the mixture separates. You
have a layer of flour with miscellaneous yeast and bacteria and a
layer of water with a touch of alcohol (whence 'hooch') and other
fermentation byproducts.

You mix the hooch in with the layer of flour when you feed your
starter otherwise you will change the water:flour ratio of your

A better way, in my opinion, to restart an old hooch layered starter
is to use a tablespoonful of the old starter to get another flour and
water mixture going as a new starter. You can get a healthier starter
faster that way.



 Subject: 29. How can I determine the proportion of flour and water
to use in my starter and dough?

Proportion of water and flour in starter and dough, and why I like
100% starters:

A recent poster related difficulty controlling and predicting the
viscosity of starters. One of the responses referred to the usual
professional baker's practice of measuring by weight, not volume.
This is the so-called "baker's percentage" (or "hydration" or
"absorption ratio"), in which the weight of each of the other
ingredients is compared to the weight of flour used. Thus equal
weights of water and flour make a 100% starter, while a typical dough
made with all-purpose flour is a 60% dough, while one made with all
"bread" flour is typically about 70%, since the extra protein can
trap a greater amount of water. Some European bakers use a variation
of this percentage system, called "dough yield".

Anyway, there is are several advantages to using a 100% starter, with
equal weights of flour and water. One is because it makes it easy to
calculate the amount of water and flour (and salt) that must be added
to the starter to make dough batches of different sizes. For example,
I like to make large loaves that weigh 1500 grams. Forty percent of
that is 600 grams of final starter that I will need when I make my
dough. Forty percent of that amount of starter is 240 grams of
intermediate starter. One-quarter of that is 60 grams, so that is the
amount of my "original" starter I begin with per loaf I will make.

Suppose I want to make about 1500g of dough at 65% baker's
percentage: I divide 1500 by 165 (100% flour, 65% water), then
multiply the result by 65 (for the total weight of water) and by 100
(for the total weight of flour) as well as by ) 0.02 (to determine
the weight of salt needed, which is typically 2%). I am going to need
909 grams of flour, and 590 grams of water, as well as 18 grams of

Now we see one advantage of using a 100% starter: since I have 600 g
of "final" starter, I have 300 g of flour and 300 g of water, and I
can subtract those amounts easily to give me 609g of flour and 290 g
of additional water, a well as 18 of salt. Adding the starter and
these amounts of flour, water, and salt will make my dough. These
easy calculations are essentially the same for any quantity of dough
you want to end up with on any given day.

The other advantage of a 100% starter is that for MOST starter
cultures a 100% starter will become ripe in 8 hours or less after
each substantial refreshment. That is easy to remember and handle--
thicker starters are often slower, although they last longer in

Finally, the acid load of a 100% culture is moderate when it is ripe,
so it will make a nicely balanced bread (flavor balance) when
appropriately handled.



 Subject: 30. How can I ship my starter to someone else?

Take refreshed starter at peak yeast activity, and add flour to make
"noodle dough".  Roll it flat so that 2/3 oz. or so fills a postal
envelope. (A postal employee wrote suggesting a cassette mailing box
available cheaply from Radio Shack -- dg)  Wrap it in cling plastic
and mail it ordinary first class.  It should be so dry as to resemble
slightly damp cardboard.

I assume a white flour starter fed and compounded with same.  A week
in the mail will not bother it.  It can be stored in the frig for
months in this form.



 Subject: 31. How do I get that lofty loaf?

Getting the lofty loaf starts way back with kneading and getting the
correct consistency (percent hydration). This is easier to do when
you weigh rather than volume-measure ingredients. Next, your
fermentation stage (after kneading, before dividing and rounding)
should not be excessively long. Sourdoughs do not have to double in
bulk in fermentation, as much of their flavor and microbiological
vigor is carried from the prefermentation stages-- from the sponge or
leaven you have made from your active starter.

The next most critical determinant of a lofty loaf is shaping. Some
people shape the finished loaf just after they have divided the
dough, which works well for plastic doughs, like high percentage rye
flour doughs. But for elastic and extensible doughs, like well
hydrated, well kneaded wheat doughs, it is better to divide, round
the loaves (pre-shape, pre-stretch the dough structure) and let them
rest about 10 minutes on the bench. Then when you finally shape them
(means just that, not just making a big lump) you will get the
necessary gluten tension to provide the lofty loaf you seek.

If you are in doubt, underproofing is better than overproofing, Of
course perfect proofing is best. But any well shaped, well proofed
loaf should be able to take slashing by a very sharp knife-- 'been
doin' it for years.



 Subject: 32. What is San Francisco Sourdough?

As I understand it, all stable "sourdough" starters are a symbiotic
mixture of yeasts and bacteria, that, through their mutual liking of
the other's by-products, cause the mixture to remain stable over
time, relatively unaffected by other wild yeasts & bacteria that may,
by chance, settle into the mix.

In the case of "San Francisco Sourdough" the protagonists have been
identified as Lactobacillus sanfrancisco (the bacteria) and
Saccharomyces Exiguus (the yeast).

These two players seem to be common in the air in the San Francisco
bay area, and hence, starter started there contains them in
abundance. Their mutual relationship gives bread made therefrom a
singular tang.

In 1995, I toured the bay area stopping at many bakeries to sample
their "sourdough".  Parisian was the most bland, though most widely
distributed; Le Bolangerie was the most tangy and "sanfranciscian";
the Village Baker, in Petaluma, was the most interesting. I did not
get to Acme in Oakland, which is deemed by some to be, well, the acme.

I, like others on this list, have attempted to duplicate the taste I
had tasted in SF, here in eastern Mass., with little success.  I have
tried inoculating commercial "San Francisco Sourdough" starter with
Lactobacillus sanfrancisco, obtained from a baking industry contact,
to little avail.  The resulting loaf _was_ "sanfranciscian" but the
starter did not retain that quality for the next batch.  I believe
both Lac. SF. and Sacc. Ex. must be in the air & the flour, or the
symbiosis will not survive in the starter.

Troy Boutte, of this list, wrote in 1995:

"Lactobacillus san francisco, when fermented by itself from a pure
culture, has an odor of canned corn early in the fermentation.  After
about 17-20 hours of fermentation under good conditions, the pH of
the ferment will drop to about 3.6 - 3.8.  At that time the odor will
have changed to a very complex and unique odor which of course makes
it impossible to compare it to anything else.

Most people say it smells like sweaty sneakers or old socks, but not
in an unpleasant way.  ... The odor comes from 40-50 small volatile
compounds that have been identified in these ferments.  Besides
lactic acid, the most abundant compounds are acetic acid (vinegar),
ethyl acetate (cross between vinegar and alcohol), and ethanol.
Other compounds are esters of short chain fatty acids that give goat
cheese and butter their respective odors and flavors.

I've found that the odor of this ferment bears little relationship
with the flavor of the bread produced.  Baking seems to mellow out
the flavor, leaving what many people consider to be an excellent
flavor to the bread."



 Subject: 33. What temperature should my starter be for best results?

Typical sourdough actually may contain three different types of microorga=

We all know about yeast and those bacilli that produce lactic acid.
There may also be different bacilli in your dough, namely ones that
produce ordinary vinegar or acetic acid.

(There is also the possibility that there are still different
microorganisms in there, but you usually don't want that to happen.
Worst example are the bacilli that produce a kind of acid that also
makes very old butter stink.)

Each microorganism has its own favorite temperature.

The bacilli that produce lactic acid like rather high temperatures of
37-40 degrees C or 99-104 degrees F.

The bacilli that produce vinegar are active only if there is yeast
that has already produced alcohol. (Yeast always does that, it never
produces gas without producing alcohol, so the word "alcohol" should
not alarm anyone.) Those bacilli like rather low temperatures, 20-25
degrees C or 68-77 degrees F.

Personally, I want lactic acid and not vinegar in my sourdough. You
can tell the two apart by the fact that lactic acid tastes sour, but
does not smell sour. Also, vinegar escapes as a gas during the baking
process as well as during storage of the bread, whereas lactic acid

Yeast will grow (multiply) fastest at 24-27 degrees C or 75-81
degrees F. (Yeast also needs oxygen to multiply.) Yeast will produce
gas fastest at a somewhat higher temperature, namely 30-32 degrees C
or 86-90 degrees F.

So, my own conclusion from all this is: the temperature which you use
to maintain the starter will, in the long run, affect the kind of
microorganisms you have in there.

If you want lots of lactobacilli, use higher temperatures when
refreshing the starter. If you refresh your starter at comparatively
low temperatures, you may get a dough that smells sour and contains a
lot of vinegar, but the resulting bread isn't all that sour.



 Subject: 34. Can I freeze or dry my starter?

With regard to freezing, I have done this for years: I put a cup of
starter in the freezer and in six months or so thaw and feed it then
refreeze.  It has always worked so I have not understood the
frequently expressed concern about freezing. I think people should
always freeze part of their starter for safety's sake. Of course,
they can always get some more from me by sending me a SASE.

(Ed. note -- be sure your starter can handle freezing like Carl's
before you rely on this method of preservation.See
"" if you would
like to obtain Carl's starter)

I only dry the starter when I know I am running out, which may be
every week or two. I prepare a batch of  starter for distribution by
combining one tablespoon of stock starter, 1/3 cup water, and enough
flour to get waffle batter consistency. I activate this mixture at
room temperature (about 70 degrees F.) until I can see small bubbles
in the body of the starter ( not frothing or hooch formation.) (The
stock starter culture is kept in the refrigerator. It is fed and
activated every two weeks or so, i.e. whenever I think about it or
need to use it.)

I pour the activated mixture into three 10-inch diameter plastic
picnic dishes to a depth of 1/8 to 1/4 inch. It dries for several
days at room temperature.  The dry starter does not stick to the
dishes. It dries on the top first, but the bottom is then exposed
with a knife. Otherwise drying would be too slow.  One could use
regular ceramic or metal dishes if you put a layer of plastic
sheeting over the dishes so the wet starter didn't stick to the dish.
Waxed paper should work as well. When it is dry and brittle I break
it up and grind it in a blender. It seems to work OK. I wonder if
other people always activate their starters before they dry them.

I leave the dried starter in the freezer for several weeks, long
enough to fill the requests that I get in the mail. Never had a
report of my starter failing to reactivate. (I test each batch before
it goes out in the mail by reactivating a portion of it to make sure
it is OK.) Well, that is just the way I do it.  Cooking is not a
mathematical science. When I learned to cook some seventy years ago
in a cattle trail chuck wagon and ranch house there were no
quantities or temperatures in recipes - just did it feel good or look
right, or taste good, and did the cowhands like it, was all there
was. This can be checked with many of the recipes from that time. We
used ones printed in the 1800s.



 Subject: 35. What happens if I start my starter with commercial yeast?

Many people believe that a starter started with commercial yeast will
eventually be "taken over" by wild yeast.  This is a good thing, and
the quality/predictability of the resultant bread should improve as
this happens, since commercial yeast isn't really designed to be used
that way.  Until that process is completed, the starter is in a state
of transition toward a desired end-state where wild yeast and
bacteria maintain a balanced, stable, symbiotic relationship.  It
follows that an evolving starter will produce breads with differing
characteristics as the nature of the starter changes.  Only a stable
starter will produce consistent results.

It can actually take quite a while for a starter (even one that began
without commercial yeast) to reach a good balance of microbiological
life.  This is one of the reasons why many bakers use cultures from
long-established starters (why go through all the time and trouble to
nurse your starter to a balanced state when there are lots of
already-balanced starter cultures out there with proven


There was an experiment done by a Dutch group: baker's yeast didn't
survive more than two refreshments of a sourdough culture. I think
that it's the acetate that kills the yeast as it is less acetate
tolerant than sourdough yeasts.



 Subject: 36. What do all these baker's terms like poolish, biga, chef, m=

Poolish-- Is French for a mixture of flour and water and a little
bakers yeast. The ratio of flour to water is 50 - 50 by weight.

Biga-- Italian for the same thing except the biga can be like a
poolish or very firm.

The above are both yeasted.

Chef-- a dough-like starter that is either an unrefreshed levain or a
piece of dough saved from the previous day's bake.

Levain-- a chef that has been refreshed with flour and water.

Biga Natural-- same as levain, but in Italian.

Mother-- this is a batter like starter of flour and water that is unrefre=

Sour-- a mother that has been refreshed with flour and water.

Mother =3D chef - it only depends on the consistency (chef dough-like,
mother batter-like). Most people here in the US call this just plain

Sour =3D levain - again it depends on the consistency of the starter.
(Sour batter-like, levain dough-like) - The difference between these
terms and the ones above is that they represent the term that
indicates that the starter is activated.

Chef, levain, biga natural, mother, and sour contain only natural
yeast cultures.

All of the above are often referred to as either starters or sponges.



Chef is a piece of dough held over to start the process of making
future doughs. It preserves the makeup of the leaven culture used at
any particular bakery. In the old days, use of la stiff (dough
consistency) chef was important because there was no refrigeration.
Stiff consistency =3D slow fermentation compared to thin consistency.
Most bakeries now use more liquid leavens, and store them in the
refrigerator when necessary.

Levain is the French term for a sponge or soft dough that is being
used to propagate a sourdough culture.

Sponge is a thinner (more watery than dough) dough stage that allows
for vigorous fermentation. It may incorporate all the water that will
eventually be in the dough, or some portion in it. When baking with
commercial yeast, a sponge allows a baker to only use one-quarter the
amount of yeast, which reduces yeast's off-flavor. When baking with
"natural ferments"-- sourdough cultures-- the culture is often
propagated in a series of sponges which are then called levains
(French), barms, leavens, starters and a few other names. I
personally have come to use the term "starter leaven" for a new
leaven culture that is being developed, the term "storage leaven" for
one that I hold over in the refrigerator, and the term "intermediate
leaven" for one that I use as a stage of propagation between the
storage leaven and the dough itself. In France and Germany there are
specific names for the three levains that make up (with the chef) the
twenty four hour cycle of the traditional small bakery.

proof -- This term is best used to describe the time of rising of the
loaves AFTER they have been shaped, although it is also used to
describe the time of rising before they are shaped. Many professional
bakers use the term "fermentation stage" for that time after mixing
and before shaping

Yeasts:commercial -- This refers to yeasts that are propagated in
nearly pure culture and (these days) usually sold in dried form. In
the past 10 years manufacturers have moved beyond "natural selection"
and the refinement of mutations-- they are now using genetic
engineering. Yeast are available with high resistance to freezing,
for example. Though most yeast packets contain some bacteria, there
are not enough to produce the acid and the volatile organic compounds
that give sourdough bread its flavor. Also, most people use so much
commercial yeast that the bread tastes more of it than of wheat. The
amount used can be reduced when bread is made with the sponge process

Yeasts:sourdough -- Bread made with natural leavens: a mixed culture
of yeast and bacterial strains recovered from environmental surfaces
(grain, grapes, etc.) and then propagated continuously by bakers.



 Subject: 37. What is the relationship between temperature and
sourdough activity?

Recent information indicates that the time-temperature relationship
is steeper than was proposed, and not quite so log-linear as had been

Through the range 40 to 75 degrees, rates may double approximately
for each 7 degrees F., rather than for each 18 degrees F. as I had
assumed.  That is based on information sent to me by Michael Gaenzle,
who, with colleagues, has studied growth rates of sourdough yeasts
and bacteria, and on (my) assumption that leavening activity and
yeast growth are mutually proportional.

Further, Michael Gaenzle (G=E4nzle) has shown that sourdough yeast
growth (for the SF sourdough yeast organism) is severely retarded by
temperatures much above 85 degrees F. and that culturing above that
temperature can deplete the yeast, leaving the lactobacillis

Michael's study was published last July in _Applied and Environmental
Microbiology_, but I have not seen it.  I have appended the
information that I have (an email received last June 28) in case some
one would like to help me speculate on how a time-temperature table
might be presented.

There is probably a simple answer about how to adjust "proofing"
times for various temperatures, but I have come to understand that I
am not exactly sure what it is just now.

Thanks to Michael for his contributions to sourdough science, and for
his interest in our discussion group.

- Dick Adams

Dear Dick Adams

Please find attached the growth rates of L. sanfranciscensis and C.
milleri as function of temperature. Growth rate is ln2/generation
time, i.e. a growth rate of 0.7 is a generation (doubling time) of
about 1 h.

The generation times measured in laboratory media are different from
that in rye / wheat / white wheat dough, however, if the generation
time at 20 C is 1/2 of that at 30 C in my medium, the organism will
also grow 1/2 as fast at 20 C compared to 30 C in dough (we checked).
So, it's not the absolute numbers that matter, but the ratio of
growth rate to growth rate at optimum temperature.

Temp  L. sf I  L. sf II Yeast (C. milleri)
2     0.019    0.016    0.004
4     0.026    0.022    0.008
6     0.035    0.031    0.013
8     0.047    0.043    0.021
10    0.063    0.060    0.033
12    0.084    0.08     0.052
14    0.11     0.11     0.078
16    0.14     0.15     0.011
18    0.19     0.20     0.16
20    0.24     0.26     0.23
22    0.30     0.29     0.30
24    0.37     0.37     0.37
26    0.45     0.46     0.42
28    0.49     0.55     0.42
30    0.61     0.64     0.35
32    0.66     0.70     0.20
34    0.66     0.70     0.05
36    0.58     0.54     0.00
38    0.39     0.31
40    0.1      0.055
41    0.00     0.00

The curves were generated by fitting the following curve to experimental =

growth rate =3D a (x^b)(e^cx)
for lactobacilli, x is (41-temperature), all temperatures are in deg.
for the yeast, x is (36-temperature), all temperatures are in deg. centig=

A, b and c were calculated as follows for the three organisms:

     L. sf I   L. sf II  Yeast

a    0.1267    0.0682    0.0124
b    1.5404    1.9782    2.9810
c   -0.1931   -0.2233   -0.3355

If I didn't make a typing error this equation should generate the
curve described above. The curve does not give the best approximation
at temperatures below 10C, though.

Transfer of the curves from our strains to your starter may change
things a bit, but nevertheless I think that it may serve as guideline
for many sourdough starters.

Let me know if you think it works (or not).

- Michael


 Subject: 38. Is there a glossary of terms?

ATCC: American Type Culture Collection (, a source for
pure strains of micro-organisms, including those that predominate in
natural leavens.

absorption: The ability of a flour to take up and hold water.
Generally higher for high-gluten flours and those with relatively
high damaged-starch levels.

acid: A solution containing free hydrogen ions, or a substance that
will release them when dissolved in water.

acid pH: Since pH is a measure of the acid/base state of a solution,
"acid pH" indicates that the solution in question is acid, and a has
a pH of less than 7 on a scale of 14.

acid tolerance: The ability of a micro-organism to grow in acid condition=

active starter: A leaven that has recently reached its equilibrium
yeast and bacterial population. If thick, it will be spongy,
tenacious, and gassy. If thin, it will be frothy and bubbly.

amylases:  Enzymes present in grain but also supplemented by millers,
capable of breaking damaged starch down to sugars and dextrins. These
sugars then power fermentation and contribute to carmelization and
the Maillard reactions (browning of the crust).

Anfrischsauer: The first stage (first expansion) of the traditional
German baking sequence, made from Anstellgut, water, and flour.

Anstellgut: The inoculant to the first stage in the three-stage
sequence of expansion of a leaven culture in the traditional German
bakery. It is a portion of the ripe sourdough from the previous day.

ash content: The mineral content of flour.

autolyse, autolysis: A rest during kneading (5-20 minutes) to allow
the dough to continue hydrating and the developing gluten to relax
before kneading is resumed and the gluten is taken to full
development. Usually done when dough is being machine-mixed.(French,

bacteria: Single celled organisms with no defined chromosomes (yeast
don't have defined chromosomes either). Neither plant nor animal.
Usually smaller than yeasts. Some can ferment, but usually don't make
CO2 in the same amounts as yeast under typical conditions-- they make
organic acids instead.

bake: Heat to an internal temperature of at least 195 degrees
Fahrenheit in a dry environment. For hearth loaves (not in a pan) the
environment should be humid initially, then dry.

baker's yeast: Strains of brewer's yeast selected and commercially
produced for raising dough.

baking yeast: Same.

batter: A thin mixture containing flour and water, in the range of
100% hydration or higher.

barm: A leaven or starter, sometimes implying one made from brewing
sediment. (English)

beer yeast: Brewer's yeast selected for making beer.

biga: Originally the same as starter or leaven (natural leaven) but
now used  to refer to a sponge raised with commercial yeast. (Italian)

bottom-fermenting yeast: Brewer's yeast (lager yeast, Saccharomyces
uvarum) which forms its fermenting mass in the bottom of a vessel of

chef: A piece of a previous batch of dough kept over to inoculate a
new flour/water mixture, which will then become a leaven, starter,
sponge (synonyms).

commercial yeast: Factory-produced yeast. The species is the same as
brewer's yeast, but the characteristics may be very different. This
term includes baking or baker's yeast.

culture: As a noun, refers to a batch of micro-organisms in a
nutrient medium, such as a flour/water mixture. Could be "pure" (one
type of organism) or "mixed" (more than one type of organism).

damaged starch: Starch granules that have been broken in milling and
are therefore accessible to water and to amylase at temperatures
below the gelatinization temperature.

detente: French term for the rest period loaves get between the
division and rounding of the dough at the end of the fermentation
stage and the shaping of the loaves.

dough: A mixture of flour and water in which the weight of the water
is in or near the range of 60-75% the weight of the flour.

Dough yield (Teigausbeute): Common expression in bakery books and
articles translated from German. Same meaning as dough hydration,
except that the number is stated as 100 parts flour plus X parts
water equals dough yield. For example, a dough yield of 171 means a
hydration of 71%.

elasticity: The springiness that allows dough with well developed
gluten to stretch and return to its previous shape.

environmental surface: In this context, refers to a surface that can
inoculate a culture, intentionally or unintentionally. It could be
the surface of a flour particle, your hands, or a bowl. The
concentration and spectrum of organisms on such surfaces vary widely,
but is much greater than is found in the atmosphere.

extensibility: The quality (seen in wheat doughs only) of thin-film
strain hardening, which stabilizes the gas cells of a rising dough
and prevents the cells from breaking. This life-like quality can be
felt in the way a good dough complies with handling.

fermentation: Usually means the conversion of sugar to carbon
dioxide, alcohol, organic acids, and organic volatiles.

fermentation stage: Usually refers to a stage in breadmaking after
dough is mixed and before loaves are divided and shaped. Sometimes
referred to as "first proof."

fungi: Plants that lack chlorophyll, ranging from yeasts and molds to

gelatinization: Uncurling and hydration of starch chains to form a
gel. Occurs as a suspension of starch granules is heated.

genetic engineering: The creation of lifeforms containing genetic
material from other species or genetic material altered in test tubes
and reimplanted into cells.

gluten: A protein complex prominent in wheat doughs. It is formed by
the association of two precursor proteins, glutenin and gliadin, and
by its strength, elasticity, and extensibility determines the
structure of the dough.

gluten window: "way of testing the level of gluten development in a
dough. Simply grab a small part of the dough between your fingers and
very gently and slowly stretch it apart. If the dough holds together
and stretches into a thin, tranluscent membrane then you've made the
window and know you've got good strong gluten.": see

hootch:The liquid layer that can accumulate in the top of a container
used to store a thin (very liquid) leaven.

humidity: The amount of water vapor (dampness) present in air.

hydration: Several meanings in this context: 1) The weight of water
in a a leaven or a dough, relative to the weight of flour. Therefore,
a dough at 70% hydration is 41% water, and a leaven at 100% hydration
is 50% water. 2) The capacity of a flour to absorb water (usually
called absorption). 3) The quantity of water in flour (related to
environmental humidity).

incubate: Encourage growth in a culture by maintaining conditions
that favor the growth of the organisms in the culture.

inoculate: To introduce a micro-organism to an appropriate medium for
its growth.

knead: To continue mixing a dough beyond the point when the
ingredients are uniformly distributed. This first causes abrasion of
flour particles, then suspension of starch granules and hydration and
linking of flour proteins.

lactobacilli: Rod-shaped bacteria that typically produce lactic acid
as the major end-product of their fermentation.

leaven: That which raises bread by producing carbon dioxide. In this
context, it is a batter, sponge, or dough that contains a mixed
culture of yeast and bacteria that has been continuously maintained
by a a series of inoculations and incubations.

levain: French for leaven.

Levain de tout point: The final leaven in the sequence of leaven
expansions in traditional French baking. Used to make up the dough.

liquid medium or media: A mixture of nutrients and water, in which
organisms may be propagated.

Malt: Dried and ground sprouted barley, high in amylase, that is
added to flour to guarantee that plenty of sugar is available to
fermentation. If excessive, leads to excessive dextrin formation,
slack doughs, and gummy crumb and crust.

mix: Used by professional bakers to include both mixing until the
dough mixture is blended AND for what others call kneading.

mutation: A change in the genetic makeup of a strain of organisms
that may lead to a change in structure or function.

mycologist: A scientist who studies fungi.

overproof: To allow the last stage of rising to last too long for the
temperature and fermentation activity of the dough. Makes slack
loaves, often with poor volume, shape, and crumb texture.

pH: A measure of the hydrogen ion concentration (on a logarithmic
scale) in a solution, from 0 to 14. Values less than 7 are acid,
while values over 7 are basic.

pointage: The fist rising after mixing (usually called the
fermentation stage). (French)

proof: Usually means the final stage of rising, after the loaves have
been shaped. Sometimes used ("first proof") to refer to the rise
after kneading and before loaves are shaped (fermentation stage), or
to a test done to see whether commercial yeast is still viable.

r.f.s.: Rec.Food.Sourdough-- Usenet group about natural leaven baking.

refreshment: Adding water and flour to a leaven to increase its
volume and feed its culture.

retarding: "Retarding simply means putting your loaves into cold
storage, the refrigerator, for awhile. This allows you to bake at a
later date, early in the morning if you wish, and it affords the
microorganisms in your dough a long, slow time to work, developing a
tastier and more sour bread." See

Sauerteig: Sourdough. (German)

selective breeding: Traditional type of genetic manipulation by
selection and propagation of  organisms with desired characteristics.

sour: In this context, means a leaven, dough, or bread high in
lactate, acetic, and other organic acids.

sourdough: A bread, dough, or leaven that contains a mixed culture of
yeast and bacteria that have given it an acid pH.

sponge: A thick batter or thin dough with hydration somewhere above
75% and a little less than 100%.

sponge leaven: A sponge that has been inoculated with a leaven
culture, then incubated until it is ripe.

stable culture: One that has been propagated through many generations
and is not changing in its microbiological composition.

starter: Something that can be used to inoculate a sourdough culture.
Essentially the same thing as a leaven.

starter sponge: A ripe leaven of sponge consistency.

starter leaven: Could be used to describe a new sourdough culture,
being propagated from an infusion of flour (or fruit) in water.

storage leaven: One that is used to preserve the culture from one
baking session to the next. Usually kept in a refrigerator.

supernatant: The same as hooch the liquid that rises to the top of a
flour/water suspension that has settled.

symbiotic association: In this context, two micro-organisms that have
complementary metabolic needs and products, and resistance to toxic
products that each other produce. This makes their mixed culture more
robust and less susceptible to disruption by a third organism that
may be introduced.

temperature: Same as the conventional meaning-- the temperature of a
leaven or a dough can be influenced by the environmental temperature,
by the process of fermentation, and by mechanical work such as
kneading. Because fermentation is more vigorous at higher
temperatures and because the relative production of fermentation
changes with temperature, control or accommodation to temperature is
important in consistent baking.

time: The conventional meaning-- but it will need to be adjusted if
temperature is not controlled.

titratable acid: The amount of acid present, regardless of the pH of
the solution. The TA may be higher than expected if the buffering
effect of ingredients (flour with a high ash/mineral content) is high.

top-fermenting yeast: Brewer's yeast (ale yeast, S. cerevisiae) which
forms its initial fermenting mass in the top of a vessel of liquid.
The progenitor of commercial bread yeasts.

Vollsauer: The third and last stage of leaven expansion in German
baking. Some of this is saved to become Anstellgut, and the rest is
used to prepare the dough.

Wild yeasts: Used casually to refer to the yeasts in sourdough
leavens and doughs. They are not "wild" anymore when they are part of
a stable culture, but the term is used to differentiate them from
commercial yeasts.

yeast: Single-celled fungi that ferment sugars and produce CO2,
alcohol, and other organic products. There are many species, usually
differentiated by their metabolic/biochemical characteristics.



 Subject: 39. What factors affect microbial growth in sourdough?

We've been doing quite some work to figure out which factors affect
microbial growth in sourdough. I've done some work in vitro (which is
about to be published: Ganzle et al., Modeling of growth of
Lactobacillus sanfranciscensis and Candida milleri in response to
process parameters of the sourdough fermentation, Applied and
Environmental Microbiology, July 1998); and a colleague of mine,
Markus Brandt, has tried to figure out how my "model predictions"
work out during the actual dough fermentation. Taken together, one
can state the following:
For sourdough lactobacilli:

A) 32=B0C - 33=B0C (89.6F - 91.4F) -- optimum growth

B) 37=B0C & 20=B0C (98.6F & 68F) -- double generation time

C) 39=B0C & 15=B0C (102.2F & 59F) --  fourfold generation time

D) 41=B0C & 4=B0C (105.8F & 39.2F) -- no growth

For the yeasts, the figures are as follows:

A) 28=B0C (82.4F) -- optimum growth

B) 32=B0C & 20=B0C (89.6F & 68F) -- double generation time

C) 34=B0C & 14=B0C (93.2F & 57.2F) -- fourfold generation time

D) 35=B0C & 8=B0C  (95F & 46.4F) -- no growth.

So: if several refreshments are done above 32 C, the yeasts will drop
out eventually. The optimum pH for lactobacilli is 5.0 - 5.5 (which
is the initial pH of a sourdough with 5 - 20% inoculum), the minimum
pH for growth is 3.8 (they usually produce acid until pH 3.6 is

Lactic or acetic concentrations don't affect growth of lactobacilli
very much: this is the reason why the buffering capacity of the flour
is so important for the organism (a high buffering capacity in high
ash flours means that the lactobacilli produce much acid until the
critical pH is reached). It also means, that in doughs that are
continuously operated with a high inoculum (more than about 30%),
you'll find more yeasts and fewer lactobacilli. Eventually, the
lactobacilli flora may change, with more acid tolerant lactobacilli
(e.g. L. pontis) prevailing. Such a sourdough is found in the Vollmar
and Meuser continuous sourdough fermentation machines (there are 6
operating in Germany, and a diploma candidate in our department
characterized the microflora of several of these: as the machine is
operated with a 50% inoculum, the pH is never above 4.1 - 4.3, and no
L. sanfranciscensis is found in those doughs).

Yeasts are different: they don't mind the pH at all, but are strongly
inhibited by acetic acid, and to a much lesser extent by lactic acid.
Increasing salt concentrations inhibit growth of lactobacilli, but
yeasts tolerate more salt. No salt is added to the sourdough until
the final bread dough, but the dough yield affects the salt
concentration: with a low dough yield (little water), the salt (ash)
is dissolved in a smaller water volume, and the salt concentration
goes up: resulting in a slower fermentation.

So much for the "in vitro" theory. Surprisingly, Markus has found
most of the predictions to come true when he was looking at the cell
counts at different temperature, size of inoculum, salt
concentration, and pH in rye dough. The variation of the inoculum
size was interesting: If he reduced the inoculum size by 2, he had to
wait almost exactly one generation time (one doubling time of the
lactobacilli) longer until the dough has reached the same cell
counts, pH, titrable acidity, and so on as the dough with the higher
inoculum. This was true for inoculum sizes between 1% and 20%: at 50%
inoculum, the pH is so low that the lactobacilli don't really grow
well, and at an inoculum size of 0.1%, the pH and/or the oxygen
pressure in the dough are so high that the cells have a lag-time (see
above) of an hour. Thus, a scanty inoculum means one generation time
longer fermentation.

The generation time of L. sanfranciscensis in rye dough at 28 C is a
little less than an hour (figures may vary with different strains in
different flours, but it's not much more or less than that), so if
the inoculation size is reduced from 20 to 2.5%, it'll take about
three hours more until the dough is ripe.

The question is, whether these findings are true for all flours and
for all organisms. The strain isolated by Kline and Sugihara does not
differ very much from the two strains I've been looking at. All the
literature available tells me that - as long as we're looking at
sourdoughs with a tradition of continuous propagation - the system
behaves the same way. Differences may be between rye flour and white
wheat flour: in white wheat flour, the enzyme activities are so low
that the organisms may run out of food before the critical pH
(lactobacilli) or the critical acetic acid concentration (yeasts) is



 Subject: 40. Should I use an established starter or make my own starter?

Well, it all depends on whether you are interested in sourdough
baking because you want to make good bread or whether you are also
interested in the challenge of creating your own sourdough starter.
Even with a predictable starter culture, sourdough baking can be
occasionally tricky. For someone who has never baked sourdough bread
before and may be experiencing trouble, beginning with a predictable
starter eliminates one possible source of trouble.

How do "established" starters get that way?  They are propagated for
years and years, generations and generations.  Also, "established"
starters are the end result of selective disposal.  For every
100-year-old starter there were countless starters that thrown away
because their properties were simply not special enough to merit
saving.  People did, in fact, give up on all those other starters.
Further, it is a relatively well-accepted fact that certain special
properties in sourdough cultures don't come into being until a
certain amount of time has passed.  For example, one can reasonably
expect that the symbiotic relationship between microorganisms that
have coexisted in a starter for several decades will be much stronger
than what is found in a months-old starter culture.  This is one
reason why these old, established sourdough cultures are such
consistent performers and are often quite resistant to
change/invasion by other sourdough microorganisms.

So the question becomes whether you want to learn how to surf or
whether you want to learn how to make your own surfboard.  Most
people would agree that it makes a lot more sense to learn how to
surf first, rather than doing both at the same time.  Billyfish
illustrates this well in his posting.  Here is a guy who has been
struggling for a long time with various starter recipes. He finally
gets some satisfaction, finally feels like he can experiment with his
technique and concentrate on making the kind of bread he wants
*after* acquiring a proven starter from SDI.  I think he sums it up
perfectly by saying "I now have a starter that is sufficiently
predictable to allow experiments to proceed."

*This* is why so many of us recommend starting with an established
sourdough culture.



 Subject: 41. Can I use metal utensils with sourdough?

A sourdough starter is acidic. Prolonged contact of your acidic
starter with metal will discolor your metal utensil and dissolve tiny
amount of the metal into the starter if you leave it for, say, weeks.
So it is not a good idea to keep a sourdough starter in a metal
container unless you want discolored, or given years of contact,
damaged utensils. Your starter, or you, may not like the small amount
of metal that is dissolved into the starter either.

So use a starter container made of a material that is not affected by
acid. My personal preference are standard wide mouth glass quart
canning jars, also known in North America as Mason jars. Mason jars
are readily available and the wide mouth makes them easy to clean.
Glass is highly acid resistant, very easy to clean and sterilize,
which makes it a preferred material for starter storage.

In the short time of mixing and rising of sourdough bread, the effect
of a slightly acidic mix is not noticeable on metal utensils, such as
spoons and bowls. So there is simply no problem in using metal
utensils, especially stainless steel utensils, to make sourdough



 42. What is a good source for technical information on sourdough starter=

Here are links to several useful and interesting technical sources :

The first four URLs are noted as "Long Technical Posts 1-4" by Dan
Wing and are correspondence from Michael Gaenzle to Dan Wing. Michael
is commenting on the first proof of Dan's book, The Bread Builders -
Hearth Loaves and Masonry Ovens' by Dan Wing and Alan Scott, an
excellent book by the way.See for my

Long Technical Post 1 by Dan Wing

Long Technical Post 2 by Dan Wing

Long Technical Post 3 by Dan Wing

Long Technical Post 4 by Dan Wing

More technical correspondence by Dan Wing

Sam Kinsey with some quotes and comments on yeast growth

Sam Kinsey with some quotes from the American Association of Cereal
Chemists site

Search over 38 years of Cereal Chemistry Abstracts at



 43. How do I convert yeast bread recipes to SD recipes?

When converting recipes to sourdough I always make sure that I build
my "sponge" with the smallest possible inoculum (usually a
tablespoon). This way, you know exactly how much water and flour you
are using (it's never easy to tell how much of what you're actually
getting when you take starter directly from the jar unless you weigh
the ingredients and maintain a 1:1 starter).

In general, I think it is a good idea to build a nice active sponge
that contains somewhere between 5% and 20% of the total flour in the
recipe.  You will want to experiment with the percentage of sponge to
see which results you like.

Here is a hypothetical example of what I mean:  Let's say that the
original recipe calls for 1000g of flour, 600g water, 20g salt and
20g yeast...  If I wanted a 20% inoculum, I would make a sponge using
200g (20% of 1000g) flour, 300g water and one tablespoon of starter.
Once the sponge was nice and active, I'd mix the sponge with 800g
flour, 300g water and 20g salt.  By using this method, I know that my
dough has exactly the same amount of flour/water as the original
recipe.  At this point, all I have to do is mix the ingredients
according to the recipe, proof and bake.  The "new" version of the
recipe should turn out very similar to the original, since the only
substantial difference is in method of leavening.

Two things to keep in mind:  1. One cannot generally do multiple
risings with sourdough as with yeast doughs.  The rising schedules
called for in the original recipe should be modified with this in
mind.  2. The defining characteristics of certain bread styles seem
fairly dependent on fast-acting yeast.  For example, a sourdough
baguette or a sourdough ciabatta will not be all that similar to the



 44. What is meant by a "fully activated" starter?

You want to mix your dough when your starter (or sponge) is fully activat=

I'd suggest that you take a few days and get to know your starter and
its cycles.  You might want to find some sort of container that you
can mark - either with a pen or a piece of tape or you can tape a
strip of paper vertically on the container and use that.  Glass
canning jars work well and you can easily see into them, or anything
else that's straight-sided (easier to judge volume increases than
flared-sided containers, like most bowls).

Take a little starter and feed it, in whatever ratio of starter to
new food you intend to use regularly (I tend to use 1 oz starter and
add 6 oz combined flour and water (or even 4 oz combined water and
flour if I'm going to be doing a number of feeding cycle), but use
what you are comfortable with).  Feed the starter and then just watch
it.  Every hour mark the container as to the level of the starter.
Check it after 12 hours.  If it's started to separate and form hooch,
feed it again.  If not, leave it for another 12 hours.

Next time you feed it, discard most of the starter (or use it bake
with or to build a sponge) and add your water and flour (I do the
same as I described above, discard down to 1 oz, add water & flour.
I add equal amounts of water and flour by weight, not by volume (I
just find it easier, and I always know how much of an amount of
starter is water and how much is flour).  This gives me a pretty
thick starter, which is my preference).

The cycle of a starter after being fed and left to sit out at room
temp is: - for a while, it looks like nothing is happening - then you
will notice small bubbles beginning to form - the volume will start
to increase - this will go on for some time, with more and more
bubbling and increasing in volume - eventually, the starter will be
fully activated.  At this point, it should be full of bubbles which
are well-integrated throughout the starter (not just on top) and it
may have a layer of foam or froth on the very top.  If you starter is
a very thin consistency, you may instead have a couple of inches of
foam on the top and not so much bubbling within the starter.  If your
starter is thick enough, it will have at least doubled in volume.
This is called the starter's "Peak". - it will stay at this level for
a some amount of time. - eventually the starter will sort of fall
back into itself, the volume will drop and the bubbling will
decrease. - at some point later, the starter will have evened out, no
bubbling will be present, and the starter will be a calm, thin batter
sitting in the bottom of your container. - eventually, it will begin
to separate and form hooch.

It's my understanding that peak yeast activity occurs while the
starter is plateauing or just starting to fall back into itself, and
that this is the optimum time to use the starter.

How long a cycle takes depends on several things: - the starter
itself, and the mix of organisms in the starter - the consistency of
the starter (thick ones take longer than thin ones) - the temperature
at which the starter is sitting (as well as the temp the starter was
when you began and the temp of the water & flour used) - possibly
your altitude (slower at high altitudes) But as a general rule, a
cycle takes 8 - 12 hours but some starters, like SDI's Russian
Starter, are much faster than that.

So, my suggestion is that you put your starter through some feeding
cycles and pay attention to what it does.  Not that you need to watch
it every minute, but check on it every hour or so and mark it's
level, or keep notes of the time and what the starter looks like.
Then you can play around with activating it at different temperatures
or different consistencies and see how that change affects it.

If you do this, you'll really get to know your starter.  You'll know
what it looks like when it's fully activated (at it's peak), or where
it is in its cycle, and how long everything takes.  This will give
you a much better handle on baking with the starter.

One thing you'll notice as you read some of the sourdough literature
is that there are discrepencies and variances with just about every
aspect of starter maintenance and baking procedures.  Keep in mind
that there is no one, true way when it comes to sourdough.  The stuff
is so flexible, adaptable and variable, that all kinds of procedures
and methods work with it.  The trick is to experiment and find out
what works for you, with your starter, in your environment.  It takes
a bit of experimentation to find that for yourself, though.  Keep
talkin' and keep readin', you'll come across lots of people's ideas
that you can try out.



 45. What about Dan Wing's new book "The Bread Builders"?

I had a very interesting book pop through the mail slot recently,
'The Bread Builders - Hearth Loaves and Masonry Ovens' by Dan Wing
and Alan Scott.

When Dan wrote me for my address so he could send me a review copy he
noted in his enthusiasm for his newly minted book "It's a really good
book." After receiving it yesterday I noted in my enthusiasm for his
newly minted book, "It's a really good book" and it is :-).

You get for your $35 the best book I have read on "natural leavens"
or sourdough. It has no recipes but sets out to teach you the basics
underlying baking bread with no commercial yeast... and succeeds very
well. The book is 254 pages, paperback, indexed, and well illustrated
with color and b&w photographs, graphs, line drawings and a glossary.

Starting out with interesting introductions by Alan Scott and Dan
Wing, the book's chapters wind their way through Naturally Fermented
Hearth Bread, Bread Grains and Flours, Leavens and Doughs, Dough
Development and Baking, Ovens and Bread.

Interspersed in the chapters are 'visits' where a separate article
describes a visit to an interesting bakery or baking related location
ranging from Vermont to California. The book's clear and easily
readable style is assisted with sidebars and notes clarifying various
points. I do like the notes in the margins as this book does rather
than at the bottom of the page.

But wait, that is only half the book. You get thrown in for free
another book, on how to design, build and operate a masonry oven. Its
chapters range through Masonry Ovens of Europe and America, Preparing
to Build a Masonry Oven, Masonry Materials, Tools and Methods, Oven
Construction, Oven Management and A Day in the Life at the Bay
Village Bakery. If you are not up to rushing out to build a masonry
oven right away, 3 methods are given to approach the results in a
masonry oven, cloche, baking stone, and you'll have to read the book
to see what I am going to be doing with a metal pot, cookie sheet and
pie plate.

All in all I believe this book is a good read for aficionados of
sourdough, and they would find it a good reference work for inclusion
in their library. As a book for someone switching from baking yeast
bread to "natural leaven" bread they would probably regard ownership
of this book as priceless gift. For someone starting out in bread
baking it would allow them to get a really good understanding without
all the "old wive's tales" that unfortunately dog some sourdough
advice. I know it will find a treasured place in my library and be
well thumbed through as it assists me in achieving the perfect loaf.

Thanks Dan.

-- Darrell

p.s. The publishers are Chelsea Green Publishing, 1 800 639 4099,, ISBN number is 1-890132-05-5, $35 also
at Amazon ~$28


 46. What's all this about natural leaven and L. sanfranciscensis?

Dan wrote: "I chose to write "natural leaven" because it is less
awkward than 'mixed ferment cultured from the environment and
sustained with repeated inoculation.'" -- Dan

Michael replied: "Sustained with repeated inoculation" is better than
anything I was writing to say the same thing. "Cultured from the
environment" is certainly true - L. sanfranciscensis and the yeasts
must come from somewhere - but somewhat misleading, as these
organisms most probably do not originate from the grain, or the flour
(Marco Gobbetti, whom I mentioned earlier has been looking for L.
sanfranciscensis on all kinds of Italian wheat flours, and he has not
found any.

In every Italian dough "sustained with repeated inoculation" you'll
find L. sanfranciscensis to be the dominating species, though. No
other scientist has been able to isolate L. sanfranciscensis from any
other source than sourdough, but all sourdough "sustained etc."
contain this organism as the dominating flora.

A possible source may be the humans: there are all kinds of
lactobacilli thriving in the mouth, the intestines, etc. Hammes met a
South African Microbiologist who claimed to have isolated L.
sanfranciscensis from the teeth of pre-school children. The data is
not published, so I don't know what science is behind this claim.
But, whereever L. sanfranciscensis comes from, it most probably does
not come from the flour.


I think it does not matter when the first batch of a new sourdough
stinks - the good bacilli will come out eventually, and they may come
faster if fermentation is done around 25 - 30=B0C (as mentionned
earlier, the temperature optimum of L. sanfranciscensis is 32 -
33=B0C). There has been nice work done in Rudi Vogels lab on the
microflora of a freshly started sourdough: first, there are
Enterobacteria (Escherichia coli, Salmonella, Enterobacter), highly
undesirable organism that stink terribly, then there are
homofermentative lactobacilli (good, but no gas production), then
acid-tolerant, heterofermentative
lactobacilli. I think, this took about 48 hours at 30=B0C. The stink at
the beginning does not matter as the organisms will be diluted out or
die eventually.

No L. sanfranciscensis, though, these will occur only after repeated
refreshments. Peter Stolz of the B=F6cker company told me that it takes
about two weeks of repeated inoculations to get a good
"sanfranciscensis" sourdough. I don't know whether or not this
process was sped up in his case as, due to his workplace, his skin is
all covered with L. sanfranciscensis.

-- Michael


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47. How does one measure the ph of sourdough, and what is the effect
of different ph's?

For sponges and doughs:

*Weigh 15 g of sponge or dough and place it in a polyethylene container.

*Add 100 ml of distilled water to this sample.

*Seal the container and shake until the sponge or dough sample has
completely dispersed.

*Place electrode(s) in the mixture and read the pH value.

*After the pH value has been obtained and recorded, slowly add 0.1N
NaOH from the buret and stir constantly until a constant pH of 6.6
is obtained. Read the buret and record the number of ml of NaOH used
(that is the TTA or Total Titritable Acidity). Take care not to add
the NaOH too rapidly to avoid going beyond pH 6.6.

For bread:

*Weigh 15g of bread, excluding the crust, into a clean dry container.

*Add 100 ml of distilled water, seal the container and shake until
bread disperses into a semi-liquid mixture.

*Determine and record pH and TTA as described for brew.

Some useful information for all you "sourheads" out there:

Overmatured sours, i.e., replenished sours matured over 8 hours at
77F, may build up excessive acidity and the lactic acid bacteria will
start to inhibit the propagation of yeast cells, i.e., slowing the
leavening activity in the sourdough.

A good and fully matured functional sour has a pH of 3.9-4.1 and a
total titratable acidity (TTA) of 13-15 ml.  Sours that develop
acidity equal to a TTA of 18-22 ml or higher with a pH of 3.8 or
lower will gradually lose their ability to produce enough carbon
dioxide to leaven bread loaves. Having a high acid content also makes
doughs softer and makes their cell structure break down during
rounding and moulding.  This tends to result in an irregular cell
structure with thicker cell walls in the bread crumb and a tougher
bite.  This effect is intensified in doughs with a relatively high
water absorption (over 62% of flour weight).  However (for all you
artisans out there), bread of this type is acceptable as "signature"
bread served in restaurants or for personal use or for artisan type

Other useful information concerning industry "normal" pH and TTA in
breads and their process:

Sourdough starter      3.9-4.1 pH      14-16 TTA

Mixed dough            4.6-4.8 pH       5-7 TTA

Proofed dough          4.2-4.4 pH       9-13 TTA

Crumb                  4.3-4.5 pH       6-7 TTA

*TTA values are expressed as ml of 0.1 N NaOH per 20g sample
(sourdough starter containing 47.6% flour) titrated to pH 6.6

**This is according to the American Institute of Baking, and not the
FDA, so I imagine that would explain some differences in "normal" pH

-- Dave


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48. Should I use more than one rise for my bread?

Some will tell you "one rise is best".  Others feel that you can get
a finer crumb with multiple risings.  Some feel that you can't get
good rise on second, or third, risings.  Others feel one rise is not
enough, that good bread requires more than one rising.

Some people report good rises on second and third risings, others say
the second stays as flat as a pancake.

Looking at the posts, I think there are a number of factors at work.
Here are some of them:

1.  The starter is an obvious difference, as some are more lively than ot=

2. The baker's technique.  A bit of gentle kneading is required
between rises or the culture (or even baker's yeast) can't get to the
nutrients in the dough.

3.  Altitude.  If someone is at a higher altitude, it's easier to get
second, third, fourth, or more risings than at lower altitudes.
Let's think in terms of higher altitudes being above a mile or so
above sea level.

4.  Flour - some flours have more nutrients than others, so some will
keep feeding the culture longer, and let the bread rise better.  Some
have more, or less, gluten which also impacts rising.  Some cultures
will degrade gluten if they are allowed to work too long, which can
tie into number 1, above.

5.  The recipe.  If the recipe provides other nutrients for the
culture, or has ingredients that interfere with the culture's
working, that can be an issue also.

6.  Expectations.  What is "a well risen loaf"?  Some people look for
big holes in their bread, others for small.  Some want a light fluffy
loaf, others want a dense loaf.  All call their loaves "well risen".

On the pan front, a pan helps a loaf hold it's shape.  To be a bit
indelicate, think of a woman past her youth with, and without, a bra.
A pan helps dough hold it's shape on five sides.  A free form loaf
has support only on the bottom.... or no support at all.  So the free
form loaf has to have good structural integrity to maintain it's
shape.  With higher hydration doughs, this becomes more of a
challenge to the baker.

-- Mike

In my opinion, people new to sourdough bread baking should remain
with one rise until they are satisfied with their bread density.
People converting their bread baking from baker's yeast should also
use one rise initially, as they will not be familiar with the
enzymatic degradation of the dough one gets with sourdough, nor be
familiar with the much slower rise times of sourdough bread.

-- Darrell


49. What is Salt Rising Bread?

Salt rising bread (SRB) is leavened by the bacterium Clostridium
perfringens rather than a yeast as used in sourdough.

I have described two reliable recipes in an article presented in
Petits Propos Culinaires No.70 (PPC is published in England and
focuses on history of cuisines and foodstuffs).

I have improved one recipe to speed the process to deliver two loaves
of SRB by mid-day after setting a pre-starter the evening before.  If
you adhere to the following, you can do the same.

In the early evening, set the pre-starter -

		  Two cups of scalded milk, immediately after
removing from heat,

		  Stir in two cups of corn meal, and

		  Three tablespoons of wheat gluten.

Cover the container loosely with plastic wrap or similar and place it
in a space that can maintain a temperature between 95 and 105 degrees
Fahrenheit.  The temperature is important - ten degrees less and
action slows dramatically.

First thing in the morning, make up the starter -
To the pre-starter, stir in,

		  One cup hot tap water (~125F),

		  One-and-a-half cup flour,

		  One-half teaspoon bicarbonate of soda.

Loosely cover the container and return it to the heat box.  In about
two hours the slurry will be covered with bubbles or foam and will
have increased volume by 10 or 15 percent.  When it reaches this

Make up the dough, add to the starter -

		  One tablespoon sugar,

		  One teaspoon salt,

		  Three tablespoons shortening (oil or solid), and

		  Flour enough to make a stiff dough (heat the flour
till warm to the touch).

Old age inspired purchase of a KitchenAid mixer; it now does the
kneading.  When making up the SRB dough, I fit the dough-hook, heat the
bowl by rinsing with hot water, and add three cups of flour plus the
starter.  I let this slurry become somewhat uniform to then continue addi=
flour until the machine  seems to groan (5 or 6 cups, perhaps).  I don't
have another rule of thumb for judging "enough" for the dough - probably
five minutes total time stirring by the time the last of the flour has be=
added.  The finished dough is somewhat sticky and seems tough.

Divide the dough in two, form loaves, and place in greased pans.  Oil
the surface, if you please.  Put the pans into the heat box for about
two hours when the dough will have risen to the pan edge.  Bake in
350F oven for an hour or until nicely browned.

Any kind of corn meal will be satisfactory (organic, inorganic,
white, yellow, stoneground, ripped to shreds by steel,
what-have-you).  Every grain I have tried has produced a satisfactory
starter.  Oak bark will inspire a starter in my experience.

The secret to a fast and reliable process is the heat and gluten.  Of
the two, the heat is probably most important.

-- Reinald

In subsequent correspondence Reinald comments:

I have made SRB for about 40 years with the early years as confused
as many people are today.  In 1981 I discovered that a fraction of
Campden tablet did a much better job of killing yeast than does salt.
A couple of years ago, after e-mail exchanges with Susan Ray Brown, I
repeated the 1981 experiments with different grains (oat meal, corn
grits, barley, etc.) and went on to try just about everything I could
find at the local natural foods store (wheat flakes, wheat bran, rye
flakes, oat bran, steel cut oats, etc.)  Practical SRB starters will
develop from all of them.

Venturing further afield, I tried slivers of bark from white oak
(Quercus alba) and black locust (Robinia pseudoacaca) as initiators
on wheat flour with Campden; again to obtain useful starters.  Next
was cheddar cheese and blue cheese and, finally, flour alone.  All

A professional food chemistry laboratory ran DNA analyses on the
Clostridium strains in flour, corn meal, and cheddar cheese mediated
starters.  The cheese Clostridium was perfringens Type A with an
exact match to their reference pattern; flour and corn had patterns
quite similar to the Type A, but not identical.

I also monitored pH of various starters as they developed.
Perfringens thrives in a basic solution even as it is producing acid
which eventually arrests activity.  Bicarbonate of soda buffers the
acid to facilitate perfringens action; it is not part of the
leavening process.

-- Reinald


Subject: 99. Authors

Dick     -Dick Adams -- dick.adams (at)

David    -David Auerbach -- auerbach (at)

Mike     -Mike Avery --

Beth     -Beth -- housewolf (at)

Troy     -Troy Boutte -- tboutte (at)

Michael  -Michael Ganzle -- michael.gaenzle (at)

Carl     -Carl Griffith -- (deceased)

Dave     -Dave J. -- thebakery (at)

George   -George Kavanagh -- GK05 (at)

Sam      -Sam Kinsey -- slkinsey (at)

Andreas  -Andreas Krueger -- andreas.krueger (at)

Matt     -Matt -- mel63 (at)

Reinald  -Reinald S. Nielsen -- n984652 (at)

Jeff     -Jeff Renner -- jsrenner (at)

Roland   -Roland Salandha -- rsaldanh (at)

Dan      -Dan Wing -- wagons (at)

Jonathon -Jonathan Youngman -- jonathan (at)

Edited by Darrell Greenwood -- darrell.web (at)

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