Preparation materials: 5 kg of sour plum (green plum), salt 1 bag, sealed glass bottle 1 piece.

1. Wash the sour plum, take it out and drain it.

2. Clean the oil-free glass bottle with boiling water and dry it.

3. Sprinkle a layer of salt on the bottom of the glass bottle, add sour plums, then pour some salt, cover the bottle cap and shake it, and finally sprinkle a layer of salt.

4. Tighten the lid and put it in a place where the sun shines and the rain doesn't reach, and let it ferment naturally. Generally, it will be eaten for about half a year without bitterness.

This is aged sour plum, which is delicious for steaming fish and braised pork, and can also be used to make sour plum ice in summer.