When fruits ferment, the sugars they contain turn into alcohol, as when apples or apple juice turn to cider or a cook macerates raspberries to make sorbet. The three types of fruit ferments are lactic, alcohol and vinegar ferments.
One of the most popular products made from fermented fruit is wine, which is the result of fermenting grapes until they produce alcohol. Of the three types of fruit fermentation, making alcohol is considered the easiest to achieve because fruit has a high sugar content. The amount and quality of alcohol produced depends on the varietal, additives and duration of fermentation.
Because of fruit’s high sugar content, it begins to ferment very quickly. In order to slow this process down so that fermentation doesn’t produce alcohol or vinegar, lactic fermentation requires use of agents such as whey, which is sometimes harvested from fresh yogurt, water kefir or kombucha. Because fermented fruits spoil quickly, usually they’re fermented in small batches.
Vinegar fermentation of fruits, the final stage, occurs naturally when acetic acid forms. This stage of fermentation results in products such as apple cider and champagne vinegars. Adding mother of vinegar, a harmless bacteria, speeds up the process of making acetic acid, which can take as long as two months.