January 19, 2015

Spontaneous Fermentation Project Part 14 -- 1 Year

This beer is a year old and admittedly I am quite surprised by how disaffected the beer has been by its coolshipped band of yeast and bacteria. Given how quickly an infection can take over a clean beer, I expected to see a lot of activity over the past year and I was encouraged in this belief by the early activity that was almost as vigorous as any beer I had pitched a sour blend into. However, after a couple months of activity I have been left with a relatively clear beer with no pellicle and these weird, hard floating discs of yeast. No brett funk and definitely no sourness. It's frustrating but it seems in line with many of the results of other people who have attempted to coolship beers, although I seem to be the only one fortunate enough to experience these floating piles of yeast. Sometimes I want to just throw in some dregs of some sour beers and bottle it in another year but I am trying to stay committed to seeing where this goes.

I believe part of what has left this beer in its current state is my coolship method. I believe leaving the beer out in multiple vessels in an extremely cold night made the beer cool too fast to pick up a healthy volume of fermenting organisms and I ended up creating conditions that favored development of sugar-consuming yeast over lactic acid bacteria. Jean Van Roy, the owner of Cantillon, in the past discussed the importance of slowly cooling the beer through the right temperature range. My experience seems in line with his contention (although who am I to even suggest he is wrong?).

I also believe the lack of preexisting bacteria and yeast in the fermentor play a role. I subscribe to the premise that coolshipped beer relies heavily on the bacteria and yeast that has taken up residence in the oak barrels after years of brews, and coolshipping new wort serves mostly to replenish the yeast and bacteria that do the heavy lifting early in fermentation and then are eliminated as the alcohol content rises and the ph lowers. With this beer I do not have any preexisting organisms to draw from so everything I need has to grow out of whatever came into the fermentor with this wort. To the extent that I have brett, pediococcus and other late-stage fermentors, they are likely few in number and in need to time to build their numbers.

So although the beer is nowhere near ready for consumption, there is definitely continued activity going on. The sweetness of the beer is declining and the weird hefeweizen type tastes are developing more towards the funky end and there is some green apple in the finish. That could be acetyldehyde produced as an intermediary product of more ethanol production in the beer. At least that is what I hope it is. There is definitely something going on with the beer so that is at least something to appreciate about the beer, even if it is going down a path that will ultimately lead to a drain pour. The ph is reading around the mid 4 range so definitely no sourness going on.

1 comment:

  1. Interesting stuff. I've had a "coolshipped" starter that I keep growing up. So far it's been super phenolic and everytime I add fresh wort it literally just plows through it. No real funkiness out of mine, although I get some rubber band character that may be from cholormines in the water combining with the yeast phenolics (I hadn't added campden to my previous starters, although on the latest I did). Interesting that your experience is largely in line with mine, even though I'm in Philly. Overnight temps were low 40s when I did mine back in November.

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