The method of making preserved eggs is as follows:

1 kg of eggs, 1 kg of water, 5-6 g of caustic soda, 2 g of black tea powder and 4 g of salt.

First, we heat the black tea powder with 3kg of water, boil the dark brown tea juice, and filter the tea leaves for later use. Then put the caustic soda into a jar prepared in advance, add 7kg of water to stir and dissolve it completely, then pour in the tea juice and salt and stir it evenly again. After these works are done, put the eggs into it, press them under the liquid surface, cover them and seal them, and marinate them at 2℃ for about 13 days, then take them out and peel them for inspection.

If the protein is solidified and transparent, take out the egg and soak it in a mixture of 5% feed liquid and 5% cold boiled water for 1-15 days. The concentration of feed liquid can be increased or decreased according to the coagulation state of protein.