This experiment involved leaving natural cider under an air lock for a few weeks and was not terribly successful but it had some mildly interesting results.
I stored apples in a cool room for several months, by which time some of the apples had turned brown and soft. I discarded the brown apples and washed the remaining healthy apples. Storing apples results gives the starches more time to convert to sugar, making for sweeter cider. I pressed the apples into cider. We drank most of the cider as-is, which was very sweet and delicious. I filled an empty wine bottle with the cider (unpasteurized with no yeast, sulfites, or other additives) and added an airlock and put it in the basement. It very gradually expelled a little bit of gas, and three weeks later I brought it upstairs to enjoy.
A bit of mold or possibly some other substance formed at the top. Sediment had settled to the bottom. In between was a surprisingly clear cider. The cider was incredibly sweet with a hint of some kind of exciting flavor, likely a result of the in-between state of fermentation. It didn’t come across as having any alcohol particularly. Pretty tasty. After having two glasses, my stomach was producing gas yielding burps and mildly uncomfortable stomach pressure for fifteen minutes or so. Lessons learned from this include:
- These orchard apples (rinsed) don’t have significant built-in yeast
- This partially fermented stuff may be a little uncomfortable on the stomach
- I was surprised to see the way it clarified and the resulting color. It looks a lot like the naturally fermented ciders at Indian Ladder
So what's next? I have several things to try:
- Press five gallons of cider, force carbonate, bottle, then pasteurize the bottles.
- Press five gallons of cider, pasteurize the cider, force carbonate, then serve directly from a keg as sparkling sweet cider. (Note: I tried this and it worked well. The only problem is, the thick/rich cider I make was not improved by adding carbonation. It's not bad, but probably just serving uncarbonated cider would have been better, so the effort wasn't worthwhile. A bit disappointing - I was hopeful this would taste a lot better.)
- Force carbonate 5 gallons of apple juice (from concentrate?)
- Put cider in bottles. Pasteurize the cider (no carbonation)
- Try a few ciders - totally unfiltered/unsettled vs. something that has settled for a few days vs. something that has settled and clarified into apple juice.
- Make apple juice from the cider (let it settle out)
- Make hard cider from 5 gallons of apple juice and force carbonate
For smaller batches of carbonated cider with something like 1% alcohol, try something like this, where yeast is added to a sealed bottle with cider. You can fill mostly glass bottles, but also at least one plastic bottle. When the plastic bottle becomes pressurized (you can tell by squeezing) you know all the bottles are carbonated. Move them to the fridge which should mostly halt fermentation.(After trying this out, I think this is a bad idea. The bottles pressurized after 24 hours and I'm just too concerned that filling glass bottles with a lot of potential pressure is really unsafe. Also, I used bread yeast, and the actively fermenting bread yeast flavor is totally unpleasant, on top of the fact that carbonation doesn't seem to improve thick dark cider, it would probably be better off uncarbonated. I took the fermenting cider from the glass bottles and consolidated them to a growler with an airlock. Also one bottle remained to which I added an airlock).