Hi everyone,
There was some discussion recently of the perennial question of how
to start a sourdough starter. This procedure has been extensively
researched by Debbie Wink, a delightful and brilliant member of our
bread making community. To the benefit of all of us, she has applied
her formal training in biology and chemistry (plus lots of additional
library and kitchen research) to arrive at the process I have
reprinted below (with her permission). Working with members of
another internet discussion group, this process has been tested and
refined by a wide variety of home bakers and thus is most likely one
of the very best around.
Best,
Allen
SHB
San Francisco
Basic Procedure for Making Sourdough Starter
by Debbie Wink
If you are the curious, investigative type (or a sourdough purist
:-), this can be done with just water in place of the juice
throughout. For many (not all), a vigorous gas-producing bacteria
will grow on day 2 and quit growing on day 3 or 4, followed by a few
days or more of agonizing stillness. The fruit juice or cider should
keep this bacteria (and a few others that are smelly) from growing
and delaying the process. Either way, the end result will be the same
sourdough starter.
Day 1: mix . . .
2 Tbl. whole grain flour* (rye or wheat)
2 Tbl. unsweetened pineapple juice, apple cider or orange juice
Day 2: add . . .
2 Tbl. whole grain flour*
2 Tbl. juice or cider
Day 3: add . . .
2 Tbl. whole grain flour*
2 Tbl. juice or cider
Day 4: (and once daily until it starts to expand and smell yeasty), mix . . .
2 oz. of the starter (1/4 c. after stirring down--discard the rest)
1 oz. flour** (scant 1/4 cup)
1 oz. water (2 tablespoons)
* Organic is not required.
** You can feed the starter/seed culture whatever you would like at
this point. White flour, either bread or a strong all-purpose like
King Arthur or a Canadian brand will turn it into a general-purpose
white sourdough starter. Feed it rye flour if you want a rye sour, or
whole wheat, if you want to make 100% whole wheat breads. If you're
new to sourdough, a white starter is probably the best place to start.
Because this is a process involving variable live cultures, I think
it may be better to outline the phases than to give a timetable. It's
a natural succession that will progress at its own speed. You can
influence it, but you can't control it--not an easy concept for a
baker :-) "Relax. Be patient." You'll hear that a lot in regard to sourdough.
You don't have to taste the mixture if the thought really bothers
you, but it will tell you a lot about the progress at times when
there may be no other outward signs. Lactic acid doesn't really have
an aroma, so you won't be able to gauge just how sour it is by smell.
Taste the initial mixture to get a point of reference and pay
attention to the sourness level as you go. Taste it before you feed
and decide if it is more sour or the same as after you fed it 24
hours previous. Taste it again after feeding the next addition to
compare in the next 24 hours.
The First Phase:
For the first day or so, nothing will happen that is detectable to
the human senses. It probably won't taste any tangier or develop any
bubbles. It will look much the same as when you mixed it. This phase
usually lasts one day, sometimes two.
The Second Phase:
The starter will begin to produce its own acid and taste tangier (it
may be hard to tell with some juices until you switch to the water).
It will expand only if the juice wasn't acid enough to prevent growth
of the gassy bacteria, otherwise there won't be much else to see.
There probably won't be much gluten degradation. It may smell a
little different on the surface, but shouldn't smell particularly
foul unless you're using water. This phase could last one to three
days or more. If it is going to get hung up anywhere, this is the
place. If after 3 days, it still doesn't become more sour and show
signs of progress, use whole grain flour instead of white for one or
more feedings.
The Third Phase:
The starter will become very tart, an indication of more lactic acid
production by a more acid tolerant bacteria. The gluten may disappear
and tiny bubbles become more noticeable. Once the starter becomes
really sour, it usually transitions right into phase four.
The Fourth Phase:
The yeast will start to grow and multiply, causing the starter to
expand with gas bubbles all over, and it will take on the yeasty
smell of bread or beer.
********************************************
Feeding Exact feeding times aren't critical. Pick a general time of
the day--morning, afternoon or evening--that will be convenient to
feed daily for 4-7 days. It'll only take a few minutes, and if it
varies a few hours from one day to the next, that's okay. But, try
not to skip a day. There is a higher incidence of growing mold when
an unestablished starter sits idle for 36 hours or more. Daily
refreshing seems to eliminate that risk.
Containers Keep the container covered to prevent mold spores, dust,
undesirable bacteria and wayward insects from falling in. Don't
worry--it doesn't need fresh air or oxygen, and all the
microorganisms you need are already in the flour.
For the first few days of this procedure, you can leave the mixture
in a bowl and set a plate on top. Saran Quick Covers work great too.
Run a rubber spatula around to scrape down the sides after mixing.
From day 4 on, it's a good idea to rinse the storage container
before returning the freshly fed mixture. It is not necessary to
sterilize the container, but old residue stuck to the sides or lid is
an invitation for mold.
By day 3 or 4 it will need room to grow (day 2 if using water). Be
sure to use a container about 4x the volume of freshly fed starter or
you may end up with a mess on your hands. Wide-mouth canning jars are
nice to gauge and view the rise. Also, the two-piece lids are
designed to vent pressure. Straight-sided Rubber Maid containers work
well too. Plastic containers with tight-fitting lids will pop their
tops if they are sealed tightly. Gladware doesn't seem to have that problem.
Temperature You don't need to keep it in a special place unless your
house is particularly cool--try to keep it in the 70's for the most
part. 75-78F would be ideal, but you needn't go out of your way to
achieve that. The low 70's will do fine. Below 68, things might be a
bit slow to develop (but it will eventually).
One solution for those with very cool houses, is to turn on a desk or
table lamp and set your container in the vicinity. Light bulbs put
out a LOT of heat, so be sure to take a temperature reading of the
site and set the starter where it won't be warmer than about 80F.
Cool is better than too warm. If the starter develops a crust at any
time, move it farther from the heat source.
The warmth helps more in the first few days because the various
bacteria really like it and it helps them produce the acids needed to
lower the pH and wake up the yeast. The yeast don't need it so warm.
Once you have a good population of yeast growing, you'll be able to
maintain it at cool room temp, even if that's less than 70F. They
will grow faster if kept warm, but they'll also run through their
food supply and exhaust themselves sooner as well.
********************************************
How it works:
It seems to be a widely held belief that if you add water to flour
and "catch" some wild yeast and sourdough bacteria from the air, or
from grape skins, etc., that they will grow and become starter, but
it doesn't work quite like that. The "bugs" we're trying to cultivate
will only become active when the environment is right -- like a seed
won't germinate until certain conditions are met. When you mix flour
and water together, you end up with a mixture that is close to
neutral in pH, and our guys need it a bit more on the acid side.
There are other microbes in the flour, however, that prefer a more
neutral pH, and so they are the first to wake up and grow. Some will
produce acids as by-products. That helps to lower the pH to the point
that they can no longer grow, but something else can, and so on,
until the environment is just right for wild yeast to activate. It is
a succession that happens quicker for some than for others. When
using just flour and water, many will grow a gas-producing bacteria
that slows down the process. It can raise the starter to three and a
half times its volume in a relatively short period--something to
behold. Not to worry, it is harmless. In fact it is a bacteria
sometimes used in other food fermentations like cheeses and
vegetables, and it is all around us in the environment, including
wheat fields and flour. It does not grow at a pH less than 4.8, and
the specified fruit juices serve to keep the pH low enough to by-pass
it. Things will still progress, but this is the point at which people
get frustrated and quit, because when the pH drops below 4.8, and it
will, the gassy bacteria stop growing. It will appear that the
"yeast" died on you, when in fact, you haven't begun to grow yeast
yet. But they will come -- really, they're already there. When the pH
drops below 3.5 - 4 or so, the yeast will activate, begin to grow,
and the starter will expand again. You just need to keep it fed and
cared for until then. Once up and running, it will tolerate a wider pH range.
Maintenance There are many opinions out there about how to maintain
sourdough starter. Feel free to refresh and store it per the cookbook
you'll be using most often. You can adjust the hydration up or down
according to recipe requirements. The way I like to maintain mine, is
to keep just 2 oz in an 8-oz jelly jar--the canning type with
two-piece lid. To feed, I measure 1 oz of it into a bowl (discard the
rest), add 1 oz bread flour and 1 oz water. Mix, then measure 2 oz of
that back into the jar (rinsed out). This is actually tripling it
since 1 oz is increased to 3 (with equal weights of flour and water),
even though I only keep 2. The measuring is easy keeping everything 1
oz. When I want to build up the volume for baking, I double, triple
or even quadruple the entire amount each time it peaks until there's
enough for the recipe and an extra 2 oz to put back in the jar. Don't
forget to save some.
The character and flavor of new starter will improve quickest with a
few more weeks of daily feeding at room temperature, but that is not
a necessity for baking with it. The flavor-producing bacterial
populations will shift and equilibrate in that time, but it is
capable of raising bread whenever the yeast are active and vigorous.
In the refrigerator, they will stay fairly active with once a week
feeding. The longer you go between feedings, the more dormant it will
become, but they can usually be resurrected with a few feedings at
room temperature. Whenever you want to raise bread with it, plan on a
few days of feeding beforehand to get it as strong as possible. You
can use discards to make pancakes, crumpets and muffins, etc.
If you want to store it in the refrigerator, first make sure it is
active and vigorous. Then when it is ready to refresh, feed it and
put it directly into the refrigerator. Most cookbooks recommend
weekly feeding to keep it in good form, but most home bakers forget
about it for weeks or months at a time. Take it out of the
refrigerator, let it come to room temperature and rise if it will.
After it peaks and starts to fall, feed and put it back into cold
storage. If it doesn't rise, feed and keep it at room temperature;
feed at least once a day until it is in good shape again. It sounds
more complicated than it is, but you'll develop a pretty good feel
for it as you go. The process is very flexible and established
starters are actually very resilient.
For the truly obsessed: To turn the starter into desem, feed with
whole wheat flour and cold water, reducing the water to achieve a
dough consistency. Knead it a bit and form it into a ball. Keep it in
a cool spot (50-65F preferably) like a basement, cellar or wine
refrigerator. Discard half and feed daily--weekly if kept in a
regular refrigerator. The key is to not allow it to get warm.