In order to make the sweet and sour tenderloin crispy outside and tender inside, the preparation of sizing batter is very important. Although the batter prepared with only milled starch is crisp, it will become sticky and soft after a long time. The solution is to add the same amount of sweet potato starch to the water mill starch.

First, mix the water mill starch and sweet potato starch evenly according to the ratio of 1: 1, then add 2-3g baking powder (only 5g baking powder can be added to 1 kg mixed starch), and then add half a bowl of water to make a batter. The consistency of batter is based on the fact that it can be pulled into a straight line when lifted with chopsticks. Then drop a few drops of cooking oil, pour in the marinated tenderloin, grab it evenly, let the batter cover the tenderloin evenly, and then fry it in the oil pan.

The reason why the same amount of sweet potato starch should be added to the water mill starch is because the sweet potato starch particles are relatively thick and can remain crisp for a long time after being wrapped in food and fried. If you only use sweet potato starch, it will not work, because the paste mixed with sweet potato starch has a high hardness after frying, and it will not work if you can't bite it.

After practice, the mixture of water mill starch and sweet potato starch in the ratio of 1: 1 has a good effect, which makes the fried tenderloin shell crisp for a long time, not easy to soften and moderate in hardness.

Baking powder is also an essential raw material for making batter, and many tiny bubbles will be generated during frying, so that the fried shell is not only crisp, but also crisp. Finally, it makes sense to add a few drops of cooking oil to the batter, which mainly plays a lubricating role, so that the tenderloin slices will not stick easily after being put into the pot.

With the appropriate batter, we should also pay attention to the re-frying method during frying. Only after two re-frying, the shell can be more crisp. The operation of re-frying is as follows: put the oil in the pot and heat it to 30% to 40%, add the tenderloin wrapped in batter, and fry it on low heat until it is 80% cooked and the surface is slightly yellow. Then the oil temperature is raised to 70% heat, and the lower tenderloin is re-fried 1 min until the surface is golden.

Because tenderloin is easy to fry, it is necessary to master the oil temperature and time. Generally speaking, when the oil temperature is 30% hot, you can put the tenderloin. If a novice in the kitchen can't accurately distinguish the oil temperature, you can put a piece of meat in the oil pan first. If the meat can float immediately, it means that the oil temperature is just right.

Because the tenderloin will be fried twice, the first frying time will not be too long, and the batter can be fished out when it turns slightly golden. When frying again, the oil temperature is raised to 70% heat, and the lower fillet is fried again 1 min, which is golden brown.