When you think of vinegar, apple cider, wine, balsamic, or spirit/alcohol/white distilled are likely the first to come to mind. However, with vinegar there are always so many possibilities since anything with sugar can ferment to alcohol and anything with alcohol can ferment to vinegar.
It would shock many people to know vinegar can come from milk, but milk has sugar like many other beverages (though in a different form). Whey vinegar, while not common, is frequently used in some locales. Its raw material is the whey from milk, treated with ultrafiltration (as shown in the main image) to remove solid proteins to leave a sugary, liquid, and refined whey.
The whey’s primary sugar is not glucose or sucrose like most beverages, but lactose. Therefore a different yeast than beer/wine yeast are used to convert the lactose to alcohol. A common yeast used is Kluyveromyces marxianus a yeast that can ferment lactose to ethanol. This ethanol is then converted to vinegar using standard vinegar manufacturing processes.
The largest use for whey to make vinegar is not whey vinegar directly, but rather whey alcohol which is distilled and used to make white distilled vinegar. This is the most popular way to make white distilled vinegar in New Zealand, which has an abundance of livestock. Granted, though it uses milk products, the distillation removes almost all proteins sparing lactose intolerant or milk allergy persons much risk.
Pure whey vinegar is sometimes sold in Central Europe, particularly Austria and Switzerland. It is yellow in color and surprisingly quite nutritious, especially with Vitamin B content.
We have not planned to offer whey vinegar, but who knows, maybe there is a market!