1. Add about 10g of old yeast into the bowl, then add warm water and stir until it melts. After it melts, add flour and stir it evenly. Just stir it into a paste, then cover it with plastic wrap and let it ferment thoroughly.

2. Now that it is fermented, let's have a look. It looks like this after fermentation.

3. Then pour it into a basin and stir it evenly. There are about two kilograms of flour in the basin, then pour in water and mix it with chopsticks. When the flour is stirred into a flocculent shape, knead it into dough. If you like the steamed bread to be softer, you can mix it with a soft one. If you want the steamed bread to be chewy, you should be a little harder. When the dough is mixed, cover it and let it ferment to twice its original size.