Washing the chestnuts with clean water, rinsing off the impurities, classifying the chestnuts according to their size, and then processing them separately. The liquid formula for cooking is consist of 80g of star anise, 50g of cinnamon, 15g of cloves, 15g of pepper, 20g of licorice, 400g of salt, 250g of sugar, and 10kg of water. The outer peel of chestnut fruit is leathery. Generally, it is difficult to be tasty if it is just be boiled or soaked. A simple vacuum infiltration method can be adopted, which means you can add water into the formula and then boiling it for 30 minutes to make a seasoning liquid. Afterward, the chestnuts could be putted into the seasoning liquid for cook.