1, but there may be some problems in the formula, such as the proportion of yeast, whether the salt is excessive, the amount of water, etc.

2. Yeast is inactive, expired or invalid. Yeast is the main driving force of bread fermentation. If something goes wrong, the bread naturally ferments badly.

3. Wrong operation during feeding, such as mixing the salt in the formula with yeast. Salt is a substance with high osmotic pressure, which will cause yeast dehydration and death.

4, the dough is not in place or overcooked, which will make it difficult to make the dough bigger and smaller, but it will not be impossible.

5. Insufficient or unavailable proofing conditions. The temperature should be 26-38 degrees and the humidity should be 65-85%, so that the growth of yeast is relatively normal. Otherwise, it will inhibit the growth and reproduction of yeast and lead to the failure of dough.

6. The fermentation process is not well controlled, and it has been over-fermented in the final fermentation of dough, and the bread will not ferment at this time.

7. The plastic operation method is wrong, the crust is damaged more and the gluten is broken. In this way, although the yeast is good, the dough has no gas holding capacity and cannot grow.