When frying chestnuts, people usually use an iron pan, but because of its unique specific heat capacity, its thermal conductivity is high. However, chestnut shell has large specific heat capacity and weak thermal conductivity. If you don't put sand in the pot when frying chestnuts, most of the heat will be absorbed by the chestnut shell, and the heat transferred to the inside of chestnuts will be very small, so it is difficult to fry chestnuts inside. Sand absorbs heat quickly. If you put sand in the pot, the heat will be transferred to the sand quickly, but at the same time the temperature will not rise quickly.

These sand stones absorb enough heat to wrap chestnuts, which can transfer heat to every side of chestnuts, so that chestnuts can not only be cooked, but also not burnt. In the process of frying, the stones in the sand and stones contact chestnuts more fully, which can make chestnuts fry faster.

The sand and gravel used for frying chestnuts are generally relatively large, and the larger the particles, the better the heat conduction, so that when frying chestnuts, it is not explosive and the frying effect is better. Moreover, in the process of frying, it is necessary to constantly turn over the sand and stones in the frying pan to make the chestnuts more slippery.