(recipe, Peter Reinhart)


Creating a barm, or mother starter, is the second step in making sourdough bread.


  1. 3½ cups (16 ounces) unbleached high-gluten or bread flour
  2. 2 cups (16 ounces) water, at room temperature
  3. 1 cup (7 ounces) Seed Culture


  1. Stir together the flour, water, and seed culture in a mixing bowl. (You can discard the remaining seed culture or give it to a friend to build into his or her own barm.) Make sure the seed culture is evenly distributed and all the flour is hydrated. It will make a wet, sticky sponge.
  2. Transfer the sponge to a clean plastic, glass, or ceramic storage container twice as large as the barm. While transferring the barm into the container, repeatedly dip your hand, spatula, or bowl scraper in water to keep the barm from sticking to it.
  3. Cover the container with a lid or plastic wrap and ferment at room temperature for approximately 6 hours, or until the barm is bubbly. The plastic wrap (or plastic lid) will swell like a balloon; when this happens, open the lid or release the plastic to let the gas escape.
  4. Replace the cover and refrigerate overnight before using. The barm will be ready to use the next day and will remain potent for three days.


Read more about making homemade bread in Melissa Lion's essay, "The sourdough apprentice."