Rye Starter - Kosher.com

Ingredients

• 2 and 1/4 teaspoons (1/4-ounce) Gefen Dry Yeast or other active dry yeast
• 1 and 1/2 cups warm water (105 to 115 degrees Fahrenheit)
• 2 cups medium or light rye flour, preferably stone-ground
• 2 medium onions, coarsely chopped and tied in cheesecloth (optional)
• 2/3 cup unbleached all-purpose flour
• 1/3 cup medium or light rye flour, preferably stone-ground
• 1 cup warm water