Vinegar is a synthetic vinegar diluted with edible glacial acetic acid, which has a strong smell but no fragrance. Glacial acetic acid has a certain corrosive effect on human body, so it should be diluted when used. Generally speaking, the content of ice vinegar should not exceed 3%~4%. This kind of vinegar does not contain any nutrients in vinegar, so it is not easy to go moldy and deteriorate. But because there are no nutrients, it can only be used as seasoning, so it is better to be jealous if it is not necessary.