Starting a “sourdough starter,” “sourdough culture,” “mother,” or “yeast baby” as I prefer, just takes some patience and persistence. You’ll need a kitchen scale to weight grams and two clean jars. One jar will hold the current batch of starter, and you will transfer just a bit of that starter into a new batch with some equal parts water and flour in order to “feed” it. Here’s a summary of what I did:
From scratch, find a clean wide-mouth jar, and rinse it thoroughly so that there is no detergent left in it. Mix in 15g flour and 15g water until it is roughly consistent in texture with no dry clumps of flour. Put it somewhere warm and dark. Wait a day. Transfer 15g of this mixture into a clean jar and add 15g flour and 15g water to it. This is called “feeding.” Keep repeating this cycle until you think you’ve lost patience. At first it will smell like boring dough, and then maybe after a week or two you’ll hit this really, really funky smell, like rotting wet socks at the bottom of a garbage can. But keep going through this stinky phase — it will start to mellow out and develop into something that still smells sour but not offensive. When you think it may be starting to mature, probably around week 3, draw a line at the top of the mixture and check back a few hours after you’ve fed it and see if it has doubled in height. If it has doubled, you’re done starting the starter! If not, keep at it, because it may take a bit longer to develop into something usable for baking.
Some people claim that there are shortcuts, like using different kinds of flour mixed in (particularly rye), or a bit of fruit juice of some sort (like pineapple). I haven’t tried these because I just hammered on with the above pattern for a month and got a really nice yeast baby that’s been with me for a few years now. My next post will be about continuing care of your yeast baby.