Ice Concentration, Separation, Refermentation, & Resurrection
Posted Apr 17th 2013 | By:
Over 2 years ago I brewed a beer that I intended to be fashioned after Dogfish Head's World Wide Stout. I brewed a big R.I.S. to around 1.100 and pitched it on top of an enormous yeast cake of 1056. I followed the standard yet advanced procedure of staggered sugar additions and pitching a second more alcohol tolerant yeast strain. By my estimates via BeerSmith, the O.G. of the beer was in the neighborhood of 1.180 after all was said and done. After several weeks primary and bulk aging in secondary with a significant raise in temperature (up to 90* ambient temp that summer) the final gravity was 1.043. The abv was too high for any yeast to really survive in there long enough to drop the FG down, even a few more points. It was syrupy sweet and almost undrinkable. It got force carbed and tucked away in the cupboard until I wanted to shock somebody with its high alcohol content, but their reaction was always the same, "This sucks...it's too sweet."
Fast forward 2 years. While reading some articles from The Mad Fermentationist, I stumble upon an article about him ice concentrating a beer:
In the article, he references how the first part that melted off of the beercicle he made was the higher alcohol portion, while the last parts to drip off were much lower abv than the original beer. This gave me an idea. If I iced my monster of a stout,collected the high alcohol portion in one container and the lower alcohol portion in another, I might be able to repitch yeast into the low alcohol portion and drop the gravity down some. I realize this sounds confusing so I tried to take pictures and illustrate the process to the best of my abilities.
Disclaimer: This breaks many sanitation and oxidation rules. I didn't care because I wanted to test my theory and maybe have a drinkable beer in the end.
IceConcentration & Separation:
First, I dumped 11 bottles of the stout into a large plastic bowl, covered it with foil and stuck it in the freezer at the coldest setting. I left it there for 2 days until I ended up with this stoutcicle.
I sanitized my giant funnel, funnel screen, 1 gallon growler, and half gallon growler. Then I stuck the funnel into the half gallon growler and put the frozen stout into the funnel to start thawing.
The idea here was that I had just over gallon of frozen beer and the first part to thaw out should be the higher alcohol portion. I let the 1/2 gallon growler fill up with the high alcohol portion.
After about 2 hours the small growler was full and I started collecting the second portion, which should be the lower alcohol portion, in the 1 gallon growler. The picture shows how much the color has changed after the first portion was thawed out and collected.
After everything was thawed and separated I was left with a half gallon growler full of less than 18%abv stout and a half gallon of greater than 18%abv in the other growler.
The strong beer portion, as I called it in the picture, was capped and put in the fridge while the weak beer was given a full packet of rehydrated champagne yeast and some yeast nutrient. After about 3 days I started to see some signs of an active fermentation via a small krausen. At this point I dumped roughly 1/3 of the strong beer into the fermenting weaker beer. This was to sort of mimic the staggered sugar additions and help the yeast stay alive via incremental feedings. Here is an illustration to help keep track of volumes between the 2 containers.
The next day I gave the fermenting growler a swirl to see if stuff was still moving since champagne yeast doesn't give off a lot of visuals. It was!
A day later I added around another 1/3 of the strong beer portion to the actively fermenting portion.
The next morning I gave it another quick swirl, it foamed up and out of the container. I had a little bit of clean up to do. I let it go an additional day before adding the final portion. I figured I'd let it dry out as much as possible and that once I added the final 1/3 it would kill the yeast.
On the day of the last addition this is where the volumes were at in case I've lost you.
I let the beer sit in the growler for about a week before I took a gravity reading. I could see a small and steady stream of bubbles during this time frame but wasn't sure if the beer was still fermenting or if it was just off gassing.
Since my refractometer is useless with this project, I pulled out the hydrometer (tested with 60* water to make sure it was calibrated) and I got a reading of right around 1.015
This is way beyond what I expected. I would have been happy with it dropping 10 points and becoming drinkable. It dropped almost 30 points and is still drinkable.
I know my OG reading was estimated and I suspect that at this alcohol level the FG reading is probably off a little even with a hydrometer but here are the final numbers.
Original Beer: O.G. 1.180 F.G. 1.043 18.8%abv
Refermented Beer: O.G. 1.180 F.G. 1.015 22.6%abv
I started with an almost undrinkable mess of a beer and ended up with a few bottles of pretty fantastic extreme beer and a great story to tell.
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