1, the mother liquor left in the salt pond after salt making with seawater or salt lake water, whose main components are magnesium chloride, calcium sulfate, calcium chloride and sodium chloride, etc., tastes bitter and toxic. After evaporation and cooling, magnesium chloride crystals are precipitated, which are called halogen blocks. Bittern dissolved in water is called brine, which is one of the coagulants commonly used in tofu production in China, and can make protein solution coagulate into gel.

2. Brine prepared by using spices such as star anise, ginger, cinnamon, tsaoko, clove, cassia twig, Senecio scandens, etc. will be bitter when the spices are added too much, especially tri-naphthalene and star anise, and more cloves will also be bitter.

3. Brine that is not properly stored and handled will also cause blistering and bitterness.

The method of removing bitterness: adding appropriate amount of rock sugar can remove bitterness and make the soup brighter.