Here’s a fun microbiology experiment you can do at home: cultivate wild yeast and a certain bacteria called lactobacillus in a culture of flour and water. Once you have a healthy colony of these little buggers, you can use them to make all sorts of great stuff. The yeast eat the flour and fart out little bubbles of gas, which cause bread to rise. Meanwhile, the lactobacilli eat the sugars in the flour and convert them into lactic acid, which provides that tangy sourdough flavor. The process we followed to raise the starter can be found here.
The basic idea is to mix together equal parts (by weight) of flour and water, and let it sit on your counter. You have to feed it more flour and water periodically so that the yeast have enough to eat, which means you’ll need to discard (or make something with!) some your starter at each feeding, so that you don’t accumulate too much. You’ll need to just discard the excess at first, until you have a stable, usable starter. This took about 10 days for me.
Early in the process you may get a rise from a type of bacteria called leuconostoc, which is not harmful, but undesirable (and stinky). This will go away after a day or two as the good yeast and bacteria grow to dominate and crowd out everything else. If your experience is like mine, you’ll see initial activity (bubbles and rising) and stinkiness from the bad bacteria, which will die out and give way to a dead period where nothing seems to be happening. If you stick with it, however, your starter will come to life with a pleasantly sour aroma (Isaac says it smells like bread), bubbling and rising until double within 8 hours of feeding. At this point you have a healthy, stable starter that you can use to make bread and other things with. You’ll want to use the starter when it is “ripe” or “mature”, that is, at full rise between 8 and 12 hours after feeding.
The starter requires consistent care and feeding, like a pet (these are living creatures you’re raising, after all). If you are going to use it often enough, you can keep it on your counter and feed it every 12 hours. Otherwise, you can keep it in the fridge for up a week before pulling it out and feeding it again (leave it out for 8-12 hours until doubled before putting it back in the fridge). You will need to give it one or two 12-hr feeding cycles at room temperature before it’s ready to use again for baking.
The first thing we tried making were Sourdough English Muffins, following this recipe. You cook these on a griddle, like pancakes. We had some trouble cooking them all the way through, and they came out a bit dense and chewy. I saw some people suggest baking them for another 5 minutes or so in a 350F oven to ensure that they bake all the way through, which should help. Nevertheless, they had a wonderful flavor, and the chewiness was pleasant, albeit different than what you expect from an english muffin. Aubrey especially loved them. We’ll give them a few more tries and post a recipe once we’ve got it perfected.