20. How much starter do I need to keep?

I think the important point in the Silverton procedure is to
frequently feed the starter so that it as active as humanly possible.
I think she committed a major screw up by stressing the volumes so
much.  Thus it would be perfectly OK to start with 1/2 a teaspoon of
starter and add 1/2 teaspoon water and flour and on the next feeding
double this to one teaspoon, then two teaspoons, 1/4 cup, 1/2 cup etc
until you have the amount of starter that you need for your recipe
and a little extra to store.  The doubling procedure is standard
practice in most sourdough recipes but there is no law saying you
have to double.  In fact, some German recipes start with a massive
dilution (one in 100) for the first feeding and then use the normal
doubling until the required amount of starter is built up.

A single teaspoon of active starter (or starter stored for a few
weeks at most in the fridge) will have tens of millions of
yeast/lactobacilli.  It is thus not difficult to rebuild the starter
from seemingly vanishingly small amounts. A thick head of bubbles
will tell you that you starter is chugging along.  Of course this
assumes you have a good starter to begin with - if you do not have a
decent starter then the frequent feeding regimen recommended by
Silverton will rapidly lead to death of your starter(?) because there
simply were not enough organisms to double at the same rate at which
you feed them.

The important point if you start with small volumes is that the
starter can dry out relatively easily - you have only 1/2 teaspoon or
one teaspoon of water to evaporate in the early steps.  Thus you
should take steps to ensure that the starter does not dry out - make
it a bit more wet than normal, for the first few feedings cover it
with a wet towel or place it in a glass which in turn is placed in a
rubbermaid container filled with a little water.  In the cold weather
I use small coolers that I fill with water at the right temperature
(85F) and then float my starter on rubbermaid boats in there - this
serves as an incubator and also keeps it relatively humid.

I am astounded that a celebrated chef like Silverton could suggest a
recipe that would end up with 7 pounds of starter that you have no
use for!  This convinces me that all cook book authors seldom
actually test their recipes or check for appropriateness for their
audience - Silverton's recipe would be fine for a bakery but
ridiculous for the average Joe or Jane that the book was written for.

-Roland