A sourdough starter is like your own personal collection of microorganisms that you can use to jump-start doughs without commercial yeast. But even more important, a starter brings the tremendous flavor that can only come from time and patience. Please read About Sourdough Starters before beginning.

Whisk together well in a large bowl:

Transfer to a bag or an airtight container. This is the flour blend you will use to feed your starter. Measure 1 ¼ cups of this flour blend into a medium container such as a quart jar or a plastic container with about a 4-cup capacity. Add to the flour:

Stir together until smooth. Cover with a piece of thin, clean kitchen towel or fabric, and secure the fabric with a rubber band. Let the starter sit at room temperature, out of direct sunlight, for several days. Check it daily. You should start to see bubbles after 3 to 5 days. If a crust forms on top, that’s okay. If the starter smells cheesy, yeasty, or nose-tinglingly sharp, your starter is alive. The only thing to look out for is mold. If any mold grows on the starter, discard it and start again.

When you see signs of fermentation, the starter is ready to be fed. It will need several more days—maybe even a week or more—of consistent feedings before it is ready to make bread.

To feed the sourdough starter, every day at roughly the same time, discard all but about ¼ cup of the starter (or see Using Discarded Starter). Add to the remaining ¼ cup starter in the container:

Adding a precise amount of flour and water is not as important as feeding the starter regularly: As long as most of the previous day’s starter is discarded and enough flour and water are added to make a thick paste, you’re doing it right. Once you get a feel for it, you may choose not to measure the flour and water at all.

As you feed the starter, try to get a sense of its behavior. It should increase in volume for several hours after being fed. At some point it will start to deflate. The smell of the starter will also change—right after feeding, it should smell mild. As the starter approaches the time for its next feeding, it will smell sharper and more acidic. Sometimes it may even smell like nail polish remover.

The starter is ready for baking when it rises and falls consistently for a few days. At least 12 hours before you plan to start making bread, discard all but about 1 tablespoon of the starter (the starter clinging to the sides and bottom of the container will be enough).

For a liquid starter, stir in:

For a stiff starter, use:

Cover and let sit until the starter has increased in volume, 8 to 12 hours. To test for readiness, drop a spoonful of starter in a cup of water. It should float. If the starter does not float, cover it and wait until it is ready. In very warm conditions, the starter may have already peaked and deflated at 8 hours. In cool conditions, it may take longer (in this case, try to place the starter in a warm location). Working with a starter is all about learning how to read its signs. This is a skill you will pick up over time.

When the starter is ready, proceed with one of the recipes below or any sourdough recipe calling for a liquid starter (for those calling for a stiff starter, see Converting a Starter).