Is it good or bad for the old vinegar to form foam

Foam of aged vinegar is a normal phenomenon, which is usually related to fermentation degree, active substance content and other factors, and does not affect food safety. Rich foam may indicate that vinegar contains more amino acids, proteins and other active ingredients, but the specific quality needs to be judged in combination with color, smell, etc.

Aging vinegar will produce a variety of organic acids and amino acids during fermentation, which are easy to form foam when shaking or dumping. The foam of the traditional aged vinegar may be more durable because it contains proteins and polysaccharides that have not been completely decomposed. The amount of foam is also related to the concentration and storage time of vinegar, and foam is more obvious in vinegar with higher concentration. If foam is accompanied with pungent odor or abnormal color, it is necessary to be alert to the possibility of deterioration.

The foam of high-quality mature vinegar is usually delicate and even, and will slowly dissipate after standing. If the foam shows large and irregular bubbles or does not fade for a long time, it may be related to the addition of thickener or improper storage. In the high temperature environment in summer, the continuous fermentation of acetic acid bacteria may also lead to the increase of foam. At this time, it should be observed whether there is turbidity precipitation. It is recommended to refrigerate vinegar after opening to avoid microbial growth affecting its quality.

When purchasing aged vinegar in daily life, you can observe the brewing process and raw material list marked on the bottle, and prioritize solid-state fermentation products. When storing, it should be placed in a cool and dark place. It is recommended to use it within three months after opening. Moderate consumption of aged vinegar can help promote digestion, but those with excessive stomach acid need to control their intake. If vinegar is found to have mold, suspended solids, or a bitter taste, it should be immediately stopped from consumption.