Also know as Liquid or Potato Yeast
I have seen over the years several Old Order Mennonite women making this for baking potato bread. It is very similar in a way to other kitchen arts, such as, making a culture for buttermilk, and could be compared to making homemade yogurt, except this is for bread. Essentially this is a way of growing more yeast. The potato starches serve as the food for the yeasts to grow on. As you will soon see in the recipe below.
When done you use part of it in baking your bread this time and reserve and refrigerate the second part until the next time.
Potato Sponge or Potato Yeast
3 medium potatoes
1 cup boiling water
1 1/2 tablespoons salt
5 tablespoons sugar
1 tablespoon dry yeast
1 cup lukewarm water
1 cup flour
Pare and cut potatoes into small pieces.
Place in sauce pan and add boiling water, cook 20-30 minutes until soft, drain and reserve potato water.
Mash with fork until smooth and add reserved potato water, adding enough cool water to make 3 cups.
Add Salt and Sugar
When mixture has cooled to lukewarm, add yeast that has been dissolved in the 1 cup lukewarm water.
Stir to mix this mixture together, and let set a couple minutes to start working, then add 1 cup flour and stir in.
I put mine in a 1/2 gallon jar, cover loosely and set in a warm place over night, (I set mine on top of the water heater)
In the morning stir the spongy mixture until well mixed. pour off 1 cup of this mixture into a jar, cover loosely and store in the refrigerator to use as a starter for the next potato sponge
I cup of the liquid yeast (sponge) may be used in place of yeast in your bread recipe. additional flour may be require in your bread recipe depending on the amount of liquid you generally use.
The starter stored in the refrigerator should keep for about one week, do not freeze.
Following are pictures of the process (not difficult) and this weekend I will post the bread recipe that I am using along with the process for that Potato Bread.