So I faithfully followed their fussy instructions: they have you start by heating a cup of milk to 90 or 100 degrees F and then remove it from the heat and stir in three tablespoons of plain yogurt and let the whole thing stand for eighteen to twenty-four hours. As you might have guessed, this isn't making sourdough starter so much as it's making yogurt. But into this yogurt you stir one cup of flour until smoothly blended and then cover tightly and let stand in a warm place until the mixture is full of bubbles and has a good sour smell. Well, it never worked, and I'd have to throw out the ingredients in disgust and disappointment, again.
I don't know if it's because you make it with a yogurt or not, but I can tell you that part of the reason it failed is because they have you cover it tightly. No wonder it never worked! Sourdough starters work by capturing wild yeasts from the air, much like Belgian beers do. If you cover it, the wild yeasts can't get in there, and you're just spoiling a cup of yogurt and a cup of flour, which is what I'd been doing all along.
Last weekend I finally got wise and called my sister. May as well go to the mountain, I figured. In talking, she mentioned that she knew that Lane Publishing later changed the instructions for sourdough starter. She had the second edition whereas I had the third, so I asked her to read me the instructions from her book. They were much, much simpler, and they worked.
Tonight we'll pull a half cup out and Steve will start a poolish, or more correctly, a levain,* for a sourdough boule. We'll also add another half cup of warm milk and half cup of flour to replenish the starter. This is called feeding it (see? the pet analogy isn't so far off) and if you don't bake often with your starter you should draw off all but a half cup of starter and add a cup each of warm milk and flour to feed it, at least once a month. The starter needs to be kept in the refrigerator once it's soured correctly, and you should leave it out on the counter from four to six hours to warm up before you use it. You can leave it overnight if you like to bake in the morning.
But woohoo! Sourdough!
In a glass or crockery jar, leave a cup of milk to stand at room temperature for 24 hours.
Add 1 cup flour and stir until smooth. Leave uncovered (very important!) in a warm place, like on top of the refrigerator (80 degrees is ideal) for 2-5 days, until it gets bubbly and smells sour, at which point you can use or cover loosely and put in the fridge until you need it.
If during its making the liquid separates, just stir it back in, but if the liquid turns pink, chuck the whole thing and start over.
I kept my starter in the only consistently warm spot in the kitchen, which is also out of the way of drafts: the top of the freezer. The next day my starter had separated, so I just stirred it back in. And today, the second day, it's ready. And it smells wonderful.
*This is pre-ferment, not preferment in pronounciation.