Notes: A true sourdough starter is nothing more than the flour and milk or water which sits at room temperature for several days and catches live yeast bacteria from the air. Most starter recipes today include yeast as an original ingredient as it is much easier and less time consuming. In addition, many sourdough bread recipes also indicate usage of yeast itself as it does provide a higher rising, lighter loaf.
A sourdough starter should be kept in a glass or plastic bowl which has a tight fitting lid. I recommend a bowl instead of a jar as you can "feed" your starter right in the bowl easily. To make your starter, mix together:
I mix the starter with an electric, hand held mixer on the lowest setting. Cover your starter and place in a warm, draft-free location for 4 to 7 days, gently stirring it once a day. You may notice that the mixture bubbles and in some cases it may even overflow the bowl. This is an indication that you have a healthy starter which should simply be poured off and discarded.
If your starter ever changes colors, to purple, for example, discard and start another one.
After allowing your starter to sit for 4 to 7 days it is ready to be used. Take out whatever portion your recipe calls for and put into the machine as you would any liquid ingredient. After removing a portion from the starter, the starter must be "fed". Simply add equal portions of milk or water and flour as was used. For example, if you used 1 cup of starter, replace it with 1 cup of water and 1 cup of bread flour.
Some hints on feeding your starter: always use the same kind of flour. If you used bread flour in your original starter, use bread flour to feed it. Also, alternate between milk and water for each feeding. Since your original liquid ingredient was milk, the first liquid feeding should be with water. If you forget which you used last, that's okay, but try to alternate at least every other time. After feeding your starter, let it sit at room temperature for about one day and then refrigerate.
Many cookbooks suggest stirring the starter once a day even when being refrigerated; I find that it is not necessary. You must, however, use a portion of the starter at least once a week. If you choose not to bake sourdough breads that often, then remove a cup of your starter and feed it as though you used some during the week. If this is not done, your starter will turn rancid and have to be replaced. Should you be away on vacation or otherwise not able to tend to the starter, freeze it. Upon your return, thaw it in the refrigerator and then remove a portion and feed it as soon as you are able.
You may be thinking that this sounds too complicated, but it really is not, nor is the starter overly fragile. A friend of mine had the same starter for 14 years!
My first few loaves of sourdough were not very sour and I feared it was my starter. After allowing the starter to mellow a little by sitting in the refrigerator and using only once a week, it and the breads became more sour.
Another hint is to put the bread in on the timer cycle for early morning baking. The milk put in the night before adds a little more sour taste. If the bread is getting too sour for you, feed with water more often than milk.
Source: The Bread Machine Cookbook by Donna Rathmell German I