The sour taste of dough indicates that the dough is over-fermented. If it is only a little sour, you can add a little alkali to knead it thoroughly to neutralize the sourness of the dough. If the acidity is moderate, you can add some dry flour and mix the dough again. When mixing the dough again, it is best to add a small amount of sodium carbonate to neutralize the sour taste.

Under certain temperature and humidity conditions, the process of making dough is to make dough fully propagate and generate gas and promote dough expansion. When yeast converts starch into sugar and consumes it in the aerobic environment inside the dough, it will release carbon dioxide gas. At this time, the volume of dough will expand and rise.

There are three kinds of leavening agents: baking soda, flour fertilizer (old flour) and dry yeast powder. They all work on the same principle: under the right conditions, the starter produces carbon dioxide gas in the dough, and then the dough becomes soft and delicious by heating and expanding. The gas released by baking soda is not rich, so the softness of the finished product made of baking soda is not very good.

The optimum environmental temperature for fermentation is between 30-35 degrees, preferably not more than 40 degrees. The humidity is between 70-75%. The environment under this data is the most favorable for dough fermentation. To test whether the fermentation is successful, you can dip your fingers in some flour and poke some holes in the dough. If the hole rebounds immediately, it means that fermentation is not enough and fermentation is needed. If the surface of the dough collapses, it means that the dough will be sour due to excessive fermentation, which can be neutralized with alkali, such as baking soda.