From wine to vinegar
Natural vinegar can only be produced out of alcoholic beverages such as cider, wine or fruit wines. Vinegar is formed by acetic bacteria out of the alcohol. The wines need to be light or slightly acetic and not too high in alcohol content (rather not higher than 8 to 10 ABV, eventually thin down).
As sulphite weakens the acetic bacteria and thus slowing down their work we recommend not to use wines which are strongly sulphurated. The wines have to be dry, as acetic bacteria transform the residual sugars into unwanted side products.
To obtain a high quality vinegar we advise to pasteurise the wine by keeping it at a temperature of 60°C for about 10 minutes. This to kill unwanted micro-organisms. At a higher temperature the alcohol would evaporate.
Cool the wine to 30 °C after pasteurisation before adding the vinegar culture. Acetic bacteria thrive well in warmth and work best at a temperature of 30 °C. Higher temperatures will kill them and at lower temperatures they become inactive

Attention:

• Don’t ever produce your vinegar at the same place where wine is fermenting.
• For vinegar production you can use wines which already are affected by acetic bacteria. But using heavily infected wines the possibility of formation of additional infections is higher. Thus this can be very harmful for the taste and odour of your vinegar. You can never obtain a fine product by starting up with a bad product.