1 c. sourdough starter
3 c. lukewarm water or potato water
3 c. flour
1 tbsp. white sugar
1 tsp. salt (unless salted potato water is used)

Add lukewarm water, salt, and sugar to starter in 2 quart jar. Mix well with spoon or fork until smooth; leave in a warm place (not hot) for several hours to "work". Store in refrigerator until needed. This is ready for use the next day.

When I want to use the sourdough, I often take it from the refrigerator and measure it out, so it is not as cold when I mix it into the recipe. Sourdough should be treated as yeast. Hot water or a hot place will kill the action of the sourdough.