Because in the frying process, the outer part is formed and hardened too quickly, the inner part will expand and the surface will crack during frying. You can try frying with low fire.

1, to fry a long doughnut, you have to use a large-caliber and large-diameter pot, and the depth of refueling must be more than twice the thickness of the fried object. Too little oil will explode unevenly or the oil temperature will rise too fast. 2. The amount of food put into the pot should be about half of the surface area of oil. If you put too much food at a time, the fishing time will be longer and the color will be darker. 3. Oil temperature control. Generally, the temperature of doughnuts is mostly180 C. If there is no thermometer, use the following method to test the oil temperature. If you put the snacks in the pot and sink them to the bottom, it is low temperature. If you sink first, and then surface immediately, it is medium temperature (170 ~ 180℃). If it doesn't sink, it will be high temperature (65430°C) when it is fried to discoloration. When the oil temperature reaches a suitable temperature, keep it at the same temperature and fry both sides until golden brown. At this point, if you stir the oil and fry it, you can fry it evenly, and a beautiful white arc appears on the edge of the dough, which means that it is fried in place. When frying doughnuts, even small bubbles on the periphery are also proof that the oil temperature is suitable), and the oil temperature is 180℃ for 6~8 minutes.