Method 1. Natural fermentation

Prepare a basin, put about a pound of flour into it, and then add the prepared warm water into it. The temperature of the warm water should be about 40 degrees. While adding warm water to the flour, stir the flour with chopsticks until the flour becomes cotton-like. Do not add any more water. Then knead the flour with your hands and knead the flour into dough. After kneading the dough, you need to prepare a clean towel to cover it tightly, and then place it in a place with a temperature of about 30 degrees to ferment the dough. The fermentation time is the longest. Fortunately, it is more than 10 hours. When the dough swells significantly and a large number of honeycombs appear, it proves that the dough has fermented, and the fermented dough is old yeast dough.

Method 2: Fermentation of cooked steamed buns

Using the fermentation method of cooked steamed buns, you need to prepare 3 steamed steamed buns with old fermented dough in advance, and then break these steamed buns into small pieces. spare. At the same time, prepare a basin, add the required flour into it, add warm water and stir it into cotton wool, then add the prepared steamed bun pieces to the flour, knead it, and knead the flour into a dough. Finally, cover it with a clean towel (it is best to cover it with plastic wrap in winter). Place the dough in a place with a temperature above 30 degrees for fermentation. When it ferments to double its original size, the old yeast dough is ready.