During those rough stretches of winter when the temperature gets to 0 and below and everyone doubles down inside their homes, we have a rare opportunity where I live in Pennsylvania to not only do a little pond ice skating but to let nature concentrate my brews through freeze distillation. Freeze distilling is in line with all of my favorite methods of “natural technology” where you really don’t have do anything. All the work is in making your alcoholic beverage of choice as you usually do.
Here I’ll describe how I doubled the alcohol of my cider by simply leaving it outside.
This technique was inspired by Sanborn C. Brown’s Wine and Beers of Old New England: A How to do History. Sanborn was a Physics Professor from MIT and a brewing hobbyist on the side. I find no better joy than discovering hidden gems like his book, so wonderfully researched with great handmade techniques, from tracking a bee’s bee-line to gather honey for your mead to this illuminating apple jack technique. It’s definitely a worthwhile addition to your collection.
Basically all you do is place your brew outside so the water will freeze. It’s that simple. Whether you remove the ice, or siphon off the liquid, you’ll be left with concentrated alcohol. (Alcohol freezes at -173 degrees.) You’ll want 0 degrees temperatures ideally, though under 10 will work too. Fluctuations in temperature from day to night are welcome as it can assist with alcohol draining out of the ice crystal lattice. But overall the colder the better. The harsher it is outside, the stronger your brew will become.
In this example I made cider from the overgrown apple trees surrounding our farm. I did the crushing, pressing, and fermenting as usual. Post-fermentation I let it hang out in a food-grade plastic bucket to prevent bursting while freezing.
When the fateful stretch of sub-zero temperatures fell upon us I joyful placed my bucket out and every day or two reached my hand in to pluck out any ice that formed. (Since where I live our weather isn’t reliably ideal for this I decided to remove the ice each time to get a feel for what was happening. Sanborn relates how some years they could just leave it out and forget about it all winter, then pour it out a low tap. Siphoning will also work.)
The first few removals had huge ice chunks. I removed them by punching a hole (as pictured) to assist with lifting out. The ice size decreased each time until I really wasn’t getting anymore and considered the process done, or as good as it’ll get in this weather. In total we had a ten day run of temperatures that never climbed above 10 degree during the day but were well under 0 at night. My cider, while I never measure it, seemed like it generally hovered around 5-6% abv and after the freeze distillation tasted much like an apple wine to me and my friends so it’s possible it could have doubled. There was an overall volume loss of probably 75%, if not more. For reference, according to Sanborn 0 degrees can get you pretty close to 15%, while you’ll need a temperature of -20 to get over 25%.
Out of curiosity I held on to the first two ice chunks and thawed them indoors for a taste. The result- water with a hint of apple essence.
Enjoy this great reason to celebrate winter’s deep freeze!