Caring for Starter
A day or so before you want to bake, remove the starter from the refrigerator. The dark layer of liquid on the top is called "hooch", and it is an indication that the starter has been stored too long without feeding. As the name implies, the hooch contains alcohol. It is said that the old sourdoughs drank the stuff. I can't imagine being that desperate for a shot of booze. If the hooch is less than an inch or so deep, just ignore it. Otherwise, pour it off and replace the liquid with water.
Pour the starter into a mixing bowl. You may have to use a spatula to encourage the last of the starter out of the bottle and into the mixing bowl.
Next, add two cups of water. Whisk the water and starter together. Whisking puts some air into the starter, helps the starter recover from storage more quickly, and also distributes the yeast and lactobacillus bacteria more evenly through the mixture.
Then add 3 cups of flour and whisk that in also. (For bakers who measure by weight, this is very close to 100% hydration.) The resulting liquid will be quite thick. You don't need to whisk it until it's absolutely smooth.
Cover the mixing bowl, and let the starter work for 12 hours or so. This feeding will start the revitalization of the starter. The yeast and lactobacillus bacteria will wake up, and become active.
After the 12 hours, the starter should be frothy and active. Add another cup of water to the starter, whisk the mixture, and then add 1 1/2 cups of flour. Put two cups of the starter back in the jar, cover it loosely, and return the jar to the refrigerator now. At this point, the starter is at its peak of health, and putting the starter back in the refrigerator right after the feeding extends its storage time considerably. If you leave the starter out of the refrigerator, it will grow, and will most likely fill the jar.
Three hours or so after the second feeding, the starter should be frothy, bubbly, active, and ready for use. If you need more starter for you baking needs, just feed it again, and let it go for another 3 hours or so. You can triple the size of your starter with each feeding.
This approach to handling your starter should prevent excess acidity from building up, and should keep your starter healthy.
The kind of flour you use to feed your starter is not critical. If you are planning a sourdough, use 1 cup of white flour and 1/2 cup of rye flour, because rye flour gives the starter a better taste.
