The slow method: two stages of fermentation
For the first production runs at Harvest Vinegar Works, Derek used a traditional two-stage fermentation process. In the first stage, fresh apple cider is allowed to ferment, with yeasts feeding on the sugars and producing ethanol as a by-product. In the second stage, special bacteria called acetobacter are allowed to feed on the ethanol, which creates acetic acid (vinegar). The vinegar is then aged in a series of oak barrels for at least two years.
The quick method: bypassing the first stage
Derek discovered that other sources of ethanol work just as well as a food source for the bacteria. One day, he had a batch of ethanol left over from a distillation run of Core Vodka. Derek carefully mixed it with apple cider, then introduced the acetic acid bacteria to the mixture in his aeration tank. To his delight, the bacteria began to produce acetic acid immediately. It turns out that with the right concentration of ethanol, the first fermentation stage can be bypassed completely. This method also makes it easier to retain the natural flavors and sweetness of the apple cider, as the acetic acid bacteria only react with the ethanol, not the sugars.