Old bread refers to bread that has been aged (for a long time) or baked (for a long time). If it refers to a variety and series, I am really ignorant. Old bread is used to make special meals. Yes, there is also a special function for correcting errors in charcoal drawings.

Second fermentation is a relatively fast (single) fermentation. It consists of two parts: dough and main dough. The dough is made first. After the first fermentation, the dough is made. Most of the remaining raw materials are added and stirred into dough, and then divided, shaped, and proofed. Compared with primary fermentation, there is an additional process of pre-fermentation of the dough, so it is called secondary fermentation.