A lister on the Artisan Distillers Forum asked for recipes or procedures for fermenting apple juice to hard cider and, I’m assuming, to distill it to Calvados, the French apple brandy. He was also warned away from hard cider by another lister who has seen cider ferment all the way to vinegar, which involves a slimy bacterial “mother” in the process. Because it’s cidering season here in the Northern hemisphere, I think my answer might be of use to some of you.
You’ve got basically two ways to go. The easiest is to put the raw unpasteurized juice in gallon jugs in the refrigerator and wait. Natural “wild” yeast will start working (the “slime” (vinegar mother) doesn’t come ’til way later), and you will gradually (because of the very low fermentation temperature) notice an increase in carbonation, a decline in sweetness, and an increase in alcohol content. NOTE: you’ll need to let out some gas every so often, which is obvious if you use plastic jugs, and not so obvious if you’re using glass jugs.
As this progresses, the cider will get better and better, fizzier and more alcoholic, until at some point the malic acid apple sourness starts to overwhelm all that goodness, and you won’t like to drink it any more. The process will give you a few months of good cider drinking, and what you can’t stand to drink at the end you can distill. Alternatively, you can wait a lot longer and the vinegar mother will start to develop and ultimately make some great vinegar.
The other way to go is to just treat it like any other fruit juice; pitch your yeast, give it some nutrients and put it in a fermenter with a fermentation lock and ferment it ’til dry, at which point it will again be too tart to drink. Set it aside and wait ’til the following summer, during which time the tartness will mellow out and it will become drinkable again. At least some of this mellowing is due to malo-lactic fermentation, where the very sour malic acid in the apples is converted to less sour lactic acid.
If you’re going to distill it, you don’t have to wait , once the fermentation is done.
Zymurgy Bob, a simple potstiller