I’ve been baking a lot of bread lately, and I decided that it was high time that I had my own starter. Having a wild yeast strain grown from the air would allow me to save money on buying dried yeast and will ultimately make for tastier bread. I’m following the instructions for a Sourdough Starter in The Cheeseboard: Collective Works.
You start with 3/4 cup rye flour and 1/2 cup cool water
After 48 hours, the yeast has begun to form:
Add 2/3 cup of bread flour (I used King Arthur All Purpose White), and let it sit for another 48 hours
On Day 5, remove 1/4 cup of the starter and discard the rest (we tried to make bread from the remainder, with mixed results). Add 1/2 cup of water and another 2/3 cup of bread flour. Cover and let sit for another 48 hours.
On day 7, repeat steps from day 5. Repeat this process until day 11.
At this point, you have a viable starter. When you use it to bake, however, make sure that you have enough starter to reserve for the next baking session. You do this by reserving at least 1/4 cup of the starter that you have in your jar and using the rest for whatever the recipe calls for (if you need to feed the starter more to get the right weight for the recipe, make sure you keep the water:flour ratio the same).
A note about storage: If you want to store your starter, cap it tightly and store it in the coldest part of your refrigerator. This will effectively put the yeast to sleep. Therefore, if you want to use it again, you’ll have to “wake it up”. When you want to do this, take it out one day in advance, stir in the alcohol layer that may have formed on top (this forms when the yeast runs out of flour to eat), and feed it as per usual (day 5 method).