Balsamic-like vinegar with another fruit. How to start vinegar production?

[u/elriba]

As you may know, balsamic vinegar's first step is to reduce grape must by heating it for hours to about 35-60 °Brix. At this point the reduced must is subject to alcoholic fermentation. When the must has reached 5-7% alcohol by volume, the process of vinegar production with acetic acid bacteria (AAB) is started.

My questions is, how can I determine if my must has reached 5-7% ABV? I do have an alcohol refrectometer, but I understand these really only work with spirits. How can I do this?

I want to use other fruits to make balsamic-type vinegars. For example, using apple cider or pineapple juice. Reducing the cider or juice until it reaches about 30°Brix and then start the process.

[u/foolofcheese]

I have made some thick syrupy vinegars but they take a long time

this based on my approach so take it for what you will

start by establishing a good colony of vinegar that you like the profile of - not all vinegars taste the same or have the same acidity

start small with what you can afford to waste - I like using a 2 quart mason jar wit a pair of coffee filters held in place with a rubber band, I would get a mother from a "live" vinegar with mother Braggs is a good start, and I would get some apple juice

a quart of apple juice and maybe a 1/4 cup of live vinegar is probably a good start

once you have succeeded in starting a good colony work up to a larger size you can still work with comfortably - gallon pickle jars are a good weight and size when fairly full

once you have established a good size source of vinegar you can attempt more expensive experiments - this feedstock can be maintained by taking vinegar out from and then adding apple juice back in to

frozen apple juice concentrate is a easy supply of high brix fruit sugar - start a second colony (if you already haven't) and start adding your high brix syrup - I have never paid attention to the details but maybe a can of concentrate to a quart of vinegar and allow to ferment

once your new high sugar ferment looks good you can start a chain of vinegars - make a copy of the first high brix vinegar and then add another can of concentrate to the first (so now it has 2 cans) - keep repeating until you have a product you like or a product you are looking to age

[u/elriba → u/foolofcheese]

Thanks u/foolofcheese for the detailed information! If I understand correctly, I can just try adding the vinegar colony from the start of the process. The acetic acid bacteria will start working by themselves when the alcohol reaches an adequate percentage. Is that correct?

[u/foolofcheese → u/elriba]

a good healthy SCOBY will convert sugar to alcohol on its own no need to ferment it to "wine"

in theory you could pour a layer of live vinegar over fruit juice concentrate (without mixing) similar to how you would brew a high brix wine

but troubleshooting would be difficult and might take several experiments to get it right if it works at all

[u/elriba → u/foolofcheese]

Wow…. I just learned that SCOBY means “Symbiotic Culture Of Bacteria and Yeast”….

There IS yeast mixed in there…. Thanks!