Back on July 28, I kicked off a test of three different types of yeast. I inoculated some Welch’s grape juice with K1 V1116, EC1118, and D-47. The K1 and EC got off to a quick, foamy start, but were mostly done after a week, and completely done after two. The D-47 was slower to get started and is still going. I didn’t want the the first two hanging out there without active CO2 production going on for too long, so with Tressa’s help, I measured and extracted them.
I moved them up to the kitchen counter and used my deconstructed auto-siphon to old-school-siphon them out into a wine thief, where I measured the specific gravity. Both were exactly at 1.000. So, fermentation was pretty complete. The Welch’s started out at about 1.098, so I was looking at about 13% alcohol there.
It had developed a thin, but notable layer of yeast down at the bottom of the carboy. The bubbles from the degassing CO2 at the top were starting to dissipate as well. I figured that it would be good to get it off the yeast residue and that the racking would speed up the degassing process. I grabbed a sip as I racked and was pleasantly surprised. It was certainly still bubbly but pleasantly acidic and not overly sweet.
The racking process left me with a bit of headspace again, but I fortunately had a bottle of Frey white hanging out in the basement. I used about half that bottle to get the level back up. (Does that count as an additive?)
One thing I’ve always seen as a blind spot for me is the selection of yeast. It’s the linchpin to the development of wine, but here I am: guessing at what to use based on what I’m reading in online charts and anecdotes. In the theme of this blog then: time to document this stuff. Let’s figure out what the differences are between the major commercial yeasts out there.
Now, yes, I did just narrow this to commercial yeast strains and cut out the wild strains that some of my favorite wines/wineries use. But that can’t really be replicated (as I have discovered!) without a great deal of trespassing in the dead of night. I could test any wild strains that are hanging out in my basement — I have heard that a former tenant a few decades ago made wine down there — but it’s hard to see that it would be replicable in the future. So if I’m going to run some tests, I’m pretty much limited to the commercial yeast strains.
The Testing Plan
So here’s the plan as it stands today: I hope to run three different trials of yeast, testing three strains each trial, in three one-gallon jugs. In an effort to keep as many variables constant as possible, I’ll be using the same juice medium and storing them in the same dark closet which typically stays in the neighborhood of 68 degrees.
I’ll run each fermentation until it stops. This may be different for the different strains, so it wouldn’t surprise me if one finished up before the others. What I hope to do is taste it once when fermentation has stopped and then again a few weeks later to see if anything has changed. As I’m writing this, I think that means that I just committed to bottling.