Easy question, possibly stupid, but I was wondering… How exactly is Vinager made?
I know it has something to do with grain, but not much more then that.
Vinegar is made when bacteria turn alcohol into acetic acid. It can be made from grain but first the sugars from grain, grapes, fruit, etc. must be turned into alcohol by yeast.
Casual home method: Open and re-cork your bottle of wine, wait a while, and see if the right bacteria got in from the air. Or keep your home brew too long before opening it.
Once you get good vinegar, filter out the “mother of vinegar” from the bottle and use it to set off more wine (cider, beer, etc) turning into vinegar.
It may be that you can buy mother of vinegar from brewing-suppliers.
Cheap vinegar is not made by fermentation but is simply dilute acetic acid, made synthetically, and coloured with caramel.
Here in the UK it is labelled as “non-brewed condiment” rather than vinegar, if made in this way. It’s the same stuff, though, whether made by fermentation or by industrial oxidation of ethanol. So don’t worry that “artifical = bad”, cos it doesn’t.
The “dilute acetic acid” mentioned above was made by chemical hydrolysis instead of bacterial fermentation. It’s like pseudo-soy sauce. Real soy sauce is made by fermentation.
How vinegar is made.
A bit of fermentation chemistry.