Tim Isganitis's List: Bread

At this point, you should have a light colored layer of starter exposed, free  of hooch and mold. Use a clean teaspoon to transfer some of the starter to a  clean bowl. Reseal the jar of starter you are trying to revive and put it back  into the refrigerator - sometimes the first attempt at revival doesn't work,  and you'll need to go back to that starter. 

  Now add 1/4 cup of water and stir the starter very vigorously. Add   3/8  of a  cup of unbleached, unbromated white flour and stir again. This is very  important, even if you are a whole grain enthusiast. Whole grain flours have  many organisms on them that would compete with the organisms in the starter you  are trying to revive. We want to give your starter the best chance of  reviving. Whole grains are great for starting a starter, but not for reviving  one. Now, start the usual maintenance feedings. Twelve hours later, another  1/4  cup of water and   3/8  cup  of flour. Every 12 hours after that, pitch half the starter  and feed it another 1/4 cup of water and   3/8  cup  of flour. While I appreciate  thrift and frugality, I would actually discard the starter at this point. You  don't know what critters are working in your starter, and until it is stable  again I'd treat it with caution.

Once a starter is reliable, the next question is how to maintain it. The three  rules apply here. Almost all the questions I get about starter failures can be  traced to a failure to follow the three guidelines. In case you missed the  other pages they are on, here they are again: 

 
1.   Sourdough starter at room temperature must be fed no less than twice a day. If  you feed it less than twice a day, it will lose vitality and eventually become  useless and die. 
 
2.   Each feeding of the starter should be enough to double its size.  
 
3.   Each feeding should be equal amounts of water and flour, by weight. You can  use about 2 parts of water to 3 parts of flour by volume as an approximation.

an   active  sourdough starter. One that can, and recently has, doubled it's size after a  feeding. If you watch a starter after it is fed, for a while it just sits  there, like someone after a big meal. It's a lag phase.  

  After that, it begins to rise as the critters produce gas which is trapped by  the dough. Sometimes I compare a starter to a sponge. If you dip a sponge in  water and pull it out, it will leak water. It's porous. Sourdough starter,  and bread dough, are held up by trapped gas, but just as a sponge leaks water,  dough leaks gas. After a bit more time the gas being produced by the starter  and the gas leaking out of the starter are at an equilibrium. How long it  takes to get there depends on your starter, the temperature of the starter and  where it's rising, the density of the sponge, the strength of the flour and a  lot of other variables. Still, sooner or later, it will reach a peak. 

  As the starter runs out of food, the gas production declines, and the starter  begins to fall again as the starter leaks more gas than is being produced. As  the starter is beginning to fall, you may see little cracks, like ravines, form  on the surface of the starter. 

  I like to use the starter somewhere in the time period where it has reached its  peak through the time it is just starting to fall. It's active then.