Vinegar has been used for centuries as a foodstuff, cleaning agent and pesticide (including for weeds). Natural vinegar, sometimes known as table vinegar, is a sustainable product. It is agricultural in origin and biodegradable. Vinegar is produced in a natural way and has a low concentration of acetic acid, i.e. between 4 and 24%. Natural vinegar is intended for consumption, but cleaning vinegar obviously is not!
Technically speaking, vinegar is an acidic liquid which is produced from alcohol fermentation. This can be alcohol from the fermentation of sugar, but also from wine, beer or cider. Fermentation into vinegar takes place by the acetic acid bacteria Acetobacter. And for that process, the temperature is just as important as the presence of oxygen, so a truly natural product.
Besides natural vinegar, there is also synthetic vinegar. The concentration of acetic acid is often higher than in natural vinegar (up to 100%). This synthetic vinegar is a residual product from fossil fuels. Read more here about the difference between natural and synthetic vinegar.
Endless shelf life
Due to the natural acid, vinegar is a preservative and does not need to be refrigerated. All vinegar has an endless shelf life so long as it is sealed. Over the years, some sediment may occur in the bottle, but this does not affect the quality.
After opening, vinegar can be kept for a year. Using vinegar that has been open for longer than a year will have no harmful effects. Only the flavor and quality may vary.