When the can is finished, tighten the lid. After cooling, the lid will collapse, so that the inside is vacuum and can be stored for a long time. But don't leave your cans too long.

The practice of canned Fructus Crataegi: 1. Wash the sand fruit. 2. According to the size of the bottle, put the sand fruit into the bottle respectively, and add the right amount of sugar and water. Don't fill the clear water too full, it will take 8-9 minutes (bottled water is sold online, but I bought canned food and finished bottles). 3. Put it in the steamer. 4. Cover the lid, don't screw it too tightly. 5. Bring the fire to a boil, turn to medium heat and steam for 40 minutes (you can steam it for a while if you like it soft and rotten). 6. Take out a tight cover, preferably covered with a towel. Be careful not to burn it. After screwing out one, take out the other and tighten it. Don't take it out together.