What is "sourdough starter"?Sourdough starter is used in baked goods because it contains an organism that is able to produce the gasses that give baked goods their lightness. This organism is a type of yeast, and is alive (until killed by the heat of baking). It feeds on carbohydrates (such as flour or sugar) and produces gas and alcohol (which the old "sourdough" miners called "hooch") as byproducts. It must be fed and protected from extremes of temperature and anything else which might kill it. Given proper care and conditions, it will live and reproduce itself for years.
My starterI have been using my starter continuously since I first got it in the mid 1960s from a package of flakes I bought in San Francisco from a small sourdough company. I don't know where that company got it. A couple of years ago, when the local (Roseburg, Oregon) newspaper did a story on sourdough baking, featuring me, a local woman called me and offered to send me some of her starter, which she said had crossed to Oregon on the Oregon Trail with her family (1840s). I could tell no difference between her starter and mine, either in action, taste, or product. As far as I could tell - without conducting scientific tests which I am not equipped to do - they were identical. I have been given other starters, but they all seemed somewhat different, which is not surprising when you remember that there are over a thousand strains of yeast that have been identified.
Increasing and storing a starterYou may increase the amount of starter simply by adding more flour and water, in the proportion of one cup of water to a heaping cup of flour, and letting it stand for 8 to 24 hours. The mixture does not have to be smooth; a few small lumps will disappear as it stands.
Store the starter loosely covered in the refrigerator, preferably in a plastic container. Use a large enough container that the starter has room to expand slightly. Never use a metal container - metal seems to inhibit its growth. Glass can be dangerous unless the cover is loose enough to allow the gasses being produced to escape. It will stay "active" for as long as four weeks without attention. If you haven't used it in the last month or so, you should probably feed it by stirring it well and then discarding about half of it and replacing the discarded amount with the same amount of flour and water (or slightly more flour). Allow it to sit for a few hours, and then refrigerate it.
Baking with a starterWhen you want to bake, or a few hours before (to allow it to come to room temperature), take it out of the refrigerator and stir it well. If it hasn't be used recently, it will have separated into a gray liquid on top and white solids on the bottom. Don't discard the liquid; simply stir everything smooth and proceed.
The usual procedure for using your sourdough starter and keeping it perpetually is to maintain a large enough starter that you will always have at least a cup or two more than you will ever need at one time. Suppose you usually use at most two cups of starter when you bake. You should then always maintain your starter volume at three or four cups. When you bake, remove the two cups you need, and immediately replenish the starter by adding two cups of lukewarm water and two (or two and a half) cups of flour, and then let it sit in a warm place for a few hours. If your recipe calls for preparation of a flour and water sourdough batter the night before, then you can simply return the two cups from the batter to the sourdough container the following morning.
Adapting yeast recipes to sourdoughThe general rule for substituting sourdough starter for yeast is to use one cup of starter for each one-ounce yeast cake, and then reduce the amounts of flour and liquid each by about one cup. If the recipe is a "quick yeast" or "quick-rise" recipe, it usually calls for double or triple the amount of yeast as a regular recipe, and the above rule does not apply. Try the recipe as an ordinary "slow" method recipe, since that's what sourdough is. For quickbreads such as biscuits and muffins, substitute starter for about one-third or one-half of the flour and reduce the liquid by that amount, and use baking soda instead of baking powder.
Sourdough recipes do not adapt well for use in automatic bread machines, which generally require doughs which rise faster than sourdough. Sourdough recipes for such machines generally require the addition of commercial yeast, which - in my opinion - defeats the purpose of using sourdough.
The "sour" in sourdoughMany people complain about their home-baked sourdough breads that they are not sour enough. This is based on a misconception. The "sour" in "sourdough" refers to the acidity of the starter, not to the finished product. Many breads made from sourdough starter are actually sweet, and should be, if you are baking muffins or cake. Yes, some breads made with sourdough starter are more sour, because there was more acidic starter in the dough to begin with, or because it had longer to act on the flour because there was less starter. Professional bakers wanting to please the public's desire for "sour" sourdough get a more sour taste by forcing the yeast to work longer. There are several ways to do this, so try them all: 1) use much less starter, and then allow more time (as much as 20 hours) for the dough to rise; 2) punch the dough down more times (three or four times, rather than two), which also forces the dough to work longer. 3) use more starter. It will require some experimentation to find out what works best for you.
Getting the crust you wantFor a crustier bread, try to make your oven moister, by having a pan of water on the oven floor and by quickly spraying a mist of water into the oven every five minutes or so, especially during the first half of the baking time. Spray the loaves with a fine (salty?) water mist just before going into the oven. A nice glaze is to boil a teaspoon of cornstarch in a half cup of water until clear, then brush it on the loaves just before going into the oven.
Drying a starter (making flakes)If you want to keep starter unused for a longer period of time than a few weeks, or if you want to send some through the mail to a friend, you can easily dehydrate it into flakes. Using starter that has been fed the day before, spread a paper-thin layer onto a sheet of plastic wrap and let it sit a day or two until it dries. It can then be broken into flakes and stored indefinitely in a dry place. Once you have a successful starter, it is a good idea to dry some as a back-up. I have heard many heart-breaking stories from people whose starter (often many years old) got thrown out by some well-meaning houseguest because it appeared to be something gone bad.
To reconstitute the flakes, put about a tablespoon of flakes into a glass or plastic bowl (not metal) that will hold about four cups. Mix the flakes with about a tablespoon of lukewarm water to form a paste. Gradually mix into the paste another cup of lukewarm water, then stir in one and a quarter cups of flour. Mix well, although the mixture does not have to be free of lumps. You should have approximately one cup of a batter the consistency of pancake batter. Cover the bowl lightly (not air-tight) and put in a warm spot where the temperature is 70 to 80 degrees Fahrenheit (not warmer). Allow it to sit overnight.
After standing, there should be bubbles covering the surface and the volume should have increased a little. If so, you now have a starter. If only a few bubbles have formed, let it sit another day. If it appears not to have changed, then the reconstitution was not successful.
Freezing starterI have not had any success in freezing starter, although others claim to have done so with good results. Water quality can also affect the starter's action, especially if the water is heavily chlorinated.
How to get a starterMany recipe books contain instructions for making a sourdough starter from scratch; however, many of them include commercial yeast - either dried or in cake form - as one of the ingredients. The result, then, is merely more of that strain of commercial yeast, not a traditional starter, which is made originally by capturing wild yeasts. Thousands of strains of yeast have been identified, and commercial bread yeast is only one of them. A starter made from wild yeast will be quite different.
You may also find instructions somewhere for making a starting by allowing some liquid (flour batter made with water, milk, yoghurt or fruit) to stand at room temperature in your kitchen for several days. If this begins to ferment, you will have captured wild yeasts that were in the food or in the air in your kitchen. They may be suitable for making good sourdough bread, or they may not. The safest way to get a sourdough starter is to get some from someone who has a successful starter.
Some starters live on a combination of flour and water. Others are based on flour and milk. Be sure that whatever starter you get, you feed it with the right liquid.
You may be able to get a suitable starter if you just inquire around locally where you live, or ask a local home economics teacher, the food editor of your local paper, or your county extension agent.
If you want to try creating a starter on your own, the following method is simple and will produce a good starter.
In a wide-mouthed plastic or glass container make a small amount of batter using two tablespoons of whole wheat flour and about one and a half tablespoons of warm water. Use bottled water if your tap water is heavily chlorinated. Cover the container loosely and let it sit at room temperature (65 - 75 F) for 24 hours. The next day, stir in more flour and water in the same amounts as before, cover it and let it sit again. Do the same thing for a total of six or seven days. After the third day you should see tiny bubbles on the surface, which indicate that a yeast is developing and producing gas. After the third day you may use all-purpose flour if you wish. At the end of six or seven days you should have about a cup and a half of starter, and you can transfer it to a permanent container and refrigerate it. If you want to store a larger quantity, simply add sufficient flour and water to make the amount you want. On day seven you will have enough starter to bake a loaf of bread with enough left over to keep feeding for next time. Just remember not to use it all, or you will have to start over!
For a news article in the local paper about a sourdough class I gave (with photos), click here.
(I am no longer able to mail out sourdough starter as indicated in that article).
To connect up via e-mail with a large group of sourdough bakers, both experienced and novice, join the Sourdough Yahoo Group at http://groups.yahoo.com/group/Sourdough. You can subscribe simply by sending a blank e-mail to email@example.com.