Chef John's Sourdough Starter

1. Day 1: Mix 70 grams flour and 70 grams water together in a container with a lid. Container needs to be large enough to accommodate another 70 grams water and flour. Cover loosely so gases can escape. Leave for 24 hours at 70 degrees F.

2. Day 2: Add 70 grams flour and 70 grams water. Stir. Cover loosely and leave for 24 hours at 70 degrees.

3. Day 3: Remove half (140 grams) of the starter. Add 70 grams flour and 70 grams water. Stir. Cover loosely and leave for 24 hours at 70 degrees.

4. Day 4 through about Day 10: Repeat Step 3 each day until starter smells fruity, yeasty, and is beautifully fermented. You can test this by seeing if the mixture doubles within 2 to 3 hours of feeding.

5. Refrigerate until needed. Most people recommend you feed the starter once a month or so (Step 3).

6. To make bread using a refrigerated starter: feed it at room temperature for two days. Use your refreshed starter to make bread on the third day. Remember to set aside 140 grams of starter and feed it again before returning it to the fridge.

Chef's Notes:

The exact number of grams seen here doesn't really matter, as long as you're using exactly the same amount of flour and water, by weight.

I use gram weights for flour and water to ensure I'm using exactly the same amount for each. 700 grams of flour equals about 5 1/2 cups; 70 grams is a scant 1/2 cup. But I do recommend using a kitchen scale to measure grams.

For best results, use bottled water; chlorine can kill the yeast/bacteria. You can also use boiled, cooled water.

You can use different kinds of flour. I like half spelt and half bread flour, but this recipe will work with pretty much any combination, including all wheat flour.

Get the recipe for Chef John's Sourdough Bread.