The temperature of the first fermentation of the dough is usually 26-28℃, and the second fermentation after shaping is usually 35-38℃, and the relative humidity is about 70-80%. There are various reasons for the bread to collapse, such as over fermentation, under baking, opening the oven during baking, and too much vibration when the bread is put into the oven after fermentation.

The fermentation time for bread is usually 40 minutes. Bread fermentation is generally divided into three stages: primary fermentation, intermediate fermentation, and secondary fermentation, each of which takes a different amount of time to complete.

Fermentation is the process by which a microorganism prepares itself, or its direct or secondary metabolites, by means of the activity of the microorganism under aerobic or anaerobic conditions. Fermentation is sometimes written as fermentation, and its definition varies depending on the context in which it is used. The term fermentation is often used to refer to some kind of decomposition of organic matter by an organism. Fermentation is one of the earliest biochemical reactions to which mankind has had access, and is nowadays widely used in the food, biological and chemical industries. It is also the basic process of bioengineering, i.e. fermentation engineering. Research on its mechanism as well as process control continues.

The anaerobic respiration of microorganisms such as yeast and lactic acid bacteria is also called fermentation.

Source: Baidu Encyclopedia: Fermentation