1. There is too much oil and water in the formula, and the appropriate amount of baking powder is not added. It will be crushed by its own weight just like not turning it upside down in time.

Solution: Adjust the formula.

2. The batter will have tendons and will shrink after cooling.

Solution: Use low-gluten flour, or use 80% medium-gluten flour and 20% cornstarch.

Note during operation: Do not stir the batter too much before adding the egg yolks. Just turn the egg yolks 6 to 7 times. It does not matter if it is uneven. After adding the egg yolks, stir for a while until the batter is even and thin. When mixing the egg yolk paste and egg white paste, you should also pay attention to mixing gently, turning it up and down, rather than mixing it in circles.

3. Protein defoaming: It is not easy to achieve dry foaming if the egg whites are not beaten enough, or if the beating is interrupted and left for a period of time before beating again, or the beating time is too long, or the timing of adding sugar is wrong...it is not easy to achieve dry foaming. The protein foam is unstable and easy to defoam. The pores are reduced, which reduces the volume of the cake batter. The cooked cake body will shrink after cooling. The egg liquid after defoaming easily precipitates and turns into a pudding layer during baking, which is also a possible reason for the cake to shrink.

Solution:

a. The egg beater and egg bowl should be clean and free of water and oil. It is best to use copper or stainless steel egg bowls.

b. The eggs must be fresh, but must be refrigerated so that the whites and yolks are separated cleanly. There should be no trace of yolk left in the whites.

c. Add sugar, white vinegar (tartar powder) and cornstarch to help whip and stabilize the foam.

d. Start beating at low speed - after roughly soaking, add 1/3 of the sugar, white vinegar (tartar powder) and corn starch, beat at medium speed, add the second step in the middle

For the third time, sugar, etc., beat continuously, do not stop for too long before beating again, until dry peaks form.