1, there is too much oil and water in the cake formula, and a proper amount of baking powder is not added, resulting in the cake being crushed by its own weight and not fluffy.

2, the batter is out of the ribs, and it retracts after cooling, resulting in no fluffy. Solution: Use low gluten flour, or 80% medium gluten flour +20% corn starch.

3. Protein defoaming: insufficient beating, or beating after stopping for a period of time, or beating eggs for too long and adding sugar at the wrong time, it is not easy to achieve dry foaming, so the protein foam is unstable, easy to defoam, and the pores are reduced, which reduces the volume of cake paste, and the cooked cake body will shrink after cooling, resulting in no fluffy.

4. The egg yolk paste is not evenly stirred, the oil is not fully emulsified, or the egg yolk paste and the protein paste are not evenly mixed, resulting in no fluffy.