Those who have dabbled in fermentation have usually attempted culturing vegetables, but when it comes to culturing fruit things start to get a little more complicated.
Fruit contains a lot more sugar than vegetables. These sugars are exactly what the microorganisms feast on to produce bacteria, acids, and yeasts in a cultured food product.
Because the sugars are so prevalent in fruit, a fruit fermentation requires close monitoring, unlike fermenting vegetables.
TYPES OF FRUIT FERMENTS
Lactic Acid Ferment
This is the type of ferment that produces the first stage of the fruit fermentation process.
There are many types of fruit alcohol ferments. Wine is the most well-known. This stage of fermentation is fairly easy to achieve due to all the sugars in the fruit.
The vinegar stage is the final stage of fermentation after alcohol. At this stage acetic acid is formed to produce things like apple cider vinegar.
ACHIEVING LACTIC ACID FERMENTATION
Lacto-fermented fruit jams and chutneys can be achieved in much the same way as lacto-fermented vegetables are produced. There are a few special considerations, however:
Fruits Ferment Faster
Fruits ferment faster and will turn to alcohol quickly, so they are not suited for long-term storage. Make fruit ferments in small batches and expect them to last no longer than a few weeks in the refrigerator.
Avoid Certain Starters
Fruit ferments need some assistance to go the direction of lactic acid fermentation rather than alcohol fermentation. Cut back a bit on salt and use either whey, water kefir, orkombucha as a starter culture. Freeze-dried vegetable starter cultures are not appropriate for culturing fruit.
Start with Chutneys
Combining fruits with vegetables is helpful in lowering the overall sugar content and slowing down the fermentation process. Fruit chutneys in which vegetables are added is a great starting point.