Recipe from Great Grandma say's to sponge on 2 cups warm milk and 1 cup warm water. What does this mean?
"A technique of mixing dough in a two stage process to produce more flavorful loaves. The first stage involves mixing a small amount of water, flour and yeast together first and giving it some time to ferment. The sponge is then mixed in with the rest of the ingredient.
Loaves produced this way requires shorter fermentation time, allow for more flexibility in timing (the sponge can be held in the fridge for longer time), develops a better flavor and requires less yeast."
A sponge ferment is usually a sticky process that uses part of the flour, part or all of the water, and part or all of the yeast of a total- or straight-dough formula. Highly liquid sponges of batter consistencies are mixed with a whip, spoon, or fork. Lower hydration, stiffer sponges are lightly mixed or kneaded just until the dough begins to develop. The sponge is allowed to rest and ferment for a period of time in an environment of a desired temperature and humidity. When the sponge's fermentation time has elapsed or it has reached a desired volumetric growth characteristic, the final dough's ingredients are added.