exBEERiment | Impact Blending The Yeast Bay Vermont Ale and WLP090 San Diego Super Yeast Has On An American IPA

Author: Greg Foster

In my unyielding quest to develop the perfect IPA, and inspired by Marshall’s comparison of WLP090 San Diego Super Yeast and the TYB Vermont Ale strain, I conceived what I thought would make an interesting xBmt. My go-to yeast has been WLP090 for over a year now, though I’ve been eager to try the Vermont strain due to the praise it’s been getting in the homebrew world. After reading that 93% of participants in the aforementioned comparison preferred the beer fermented with Vermont Ale over the one made with San Diego Super Yeast, I knew I had to get my hands on some immediately.

There was just one big glaring issue I had with Vermont Ale yeast, a recurring issue reported by many users of this strain– low attenuation. Over my years of homebrewing, I’ve developed a strong preference for bone dry West Coast style IPA, as it seems to allow the hops to shine. In my mind, an IPA finishing at 1.017 SG is just unacceptable. Not that it would be a disaster, obviously it wasn’t, but I can’t imagine a scenario where a dryer version wouldn’t be better. If Vermont Ale yeast is really that good, then dammit, I’m going to try it, but I’m unwilling to compromise on my demand for a well attenuated beer. What to do?! That’s when the idea hit me:

Combine both yeasts to create a super ultra mega yeast!

| PURPOSE |

To evaluate the differences between a split batch of the same wort where half was fermented with a single strain (TYB Vermont) and the other a blend the same yeast and another strain (TYB Vermont + WLP090).

| METHODS |

It’s commonly accepted that delicious fruity esters are created largely during the first couple days of fermentation, since this is what I wanted in my beer, I chose to start by pitching only the Vermont Ale yeast. Then, during the second half of the fermentation, I would add a decanted starter of Super San Diego yeast. I’d then pray to the yeast gods that the second yeast would drive the beer down to a much lower and drier finishing gravity, all without stripping away any hypothetical Vermont yeast flavor benefits. The only thing left was to devise a dry ultra hoppy IPA recipe worthy of this test.

Super San Vermont IPA Recipe

Fermentables

Hops

Hop blend consisted of 42 g each of Citra and Centennial and 36 g each of Cascade, CTZ, Amarillo, and Simcoe

Yeast

My yeast starter procedure for this xBmt might be viewed as slightly unconventional to some, but it works well for me given my smaller batch sizes. A couple weeks prior to brewing, I propagated the yeasts in wort I’d previously pressure canned, splitting a single vial of Vermont Ale between 6 jars and a single vial of WLP090 between 4 jars, each 2 quart jar containing approximately 1500 mL of 1.032 SG wort. By brew day, the starters had completely fermented out.

Brew day had arrived! I mashed the grains at 145°F, the lowest I’ve ever done, and let it rest for 90 minutes in hopes of increasing the chances of good attenuation. Another first for me, I decided to try using hop extract for a clean bitterness.

This lead to an unusually yellow hot break that admittedly freaked me out a little bit.

The boil continued and I added hops per the recipe. I got a little creative when it came to the flameout hop additions by combining them all in a single jar, mixing them up vigorously, then separating them into 4 equal amounts and adding them to the wort every 10°F drop starting at 205°F. It took about 45 minutes to empty the jar of hops, after which I let it steep an additional 15 minutes to make it an even hour before chilling. The wort was then evenly split into 2 corny keg fermentors and placed in my fermentation chamber. I proceeded to pitch 2 Vermont Ale starter jars, which had been cold crashed and decanted, into each batch. It certainly lived up to its reputation, taking off quickly and fermented vigorously. I took a hydrometer reading after 24 hours of active fermentation and found it was at 1.028 SG.

Perfect! With fermentation about half complete, it was time to add the San Diego Super Yeast. I pitched a single jar of crashed and decanted WLP090 starter into one of the fermenting beers.

After another 5 days, both fermentations appeared to have finished fermenting. This was the moment I’d been waiting for, an awkwardly exciting moment of truth, it was time to check and compare FGs– did my theory work?!

I first took a hydrometer reading of the Vermont-only batch and found it was sitting at a respectable 1.014 SG, a bit lower than I expected for this strain given the stories I’d heard. In my mind, the blended yeast batch should have done at least as well, if not finishing lower due to the addition of the arguably more attenuative WLP090. I anxiously pulled a sample of the blended yeast batch, dropped my hydrometer in, and let it settle before having a peek… 1.009 SG. Success!

It appeared my yeast combination was working exactly as I’d hoped, driving the gravity of my IPA down into bone dry territory. I waited a couple more days to check the SG again and discovered, to my surprise, the yeasts had continue to work. Far surpassing my expectations, the Vermont-only beer ended up finishing at a very respectable 1.009 SG, though the blended yeast batch won the dryness war by finishing at 1.007.  This would end up being the driest IPA I’ve ever made. Sips of the hydrometer samples were promising as both beers tasted quite delicious.

The time had come to dry hop. I pressure transferred each beer from its fermentation keg to a “secondary” keg in which the dry hops had already been added, using a small stainless mesh sheath over the dip tube as a filter. After a week on the dry hops, I crashed the beers then transferred them to separate 3 gallon serving kegs. A few days later, they were carbonated and ready for serving!

I found it interesting the blended yeast beer wasn’t as clear as the Vermont-only batch, as WLP090 is known for producing clear beer while Vermont has a reputation for being a fairly poor flocculator.

| RESULTS |

The majority of the data for this xBmt was collected during a Strand Brewers Club meeting held at South Bay Brewing Supply. Included among the 14 participants were 2 BJCP judges, 1 BJCP provisional judge, 7 experienced homebrewers, and 4 craft beer drinking friends. Unfortunately, I was unable to collect more data due to a… ahem… leaking tap. Yeah.

Each participant was provided 3 samples of beer and asked to determine the one that was different from the others. In order to yield a statistically significant result give the sample size, 9 participants would have had to correctly identify the different beer (p<0.05), while ultimately only 6 did so (p=0.45). Since the kegs mysteriously kicked so quickly, I thought it’d be interesting to provide a dirty and arguably not-good-science extrapolation assuming I’d been able to administer the triangle test to more participants– in order to reach statistical significance, 4 out of 4 additional participants (n=18, correct=10) would have had to correctly identify the odd-beer-out, the chances of which seem pretty slim to me. Either way, the results of this xBmt suggests an IPA fermented with Vermont Ale yeast alone is not reliably distinguishable from the same IPA fermented with Vermont Ale yeast with WLP090 San Diego Super Yeast added 24 hours into active fermentation.

The 6 participants who selected correctly moved on to a comparative evaluation of the different beers, only 5 of whom chose to respond. It’s always fun to analyze this data, though it behooves us all to remember it is essentially meaningless since the xBmt failed to achieve statistical significance. Please interpret the following with a gigantic grain of salt.

Regarding aroma, 4 tasters thought the beers were somewhat similar and 1 perceived them as smelling exactly the same. Preferences as to which had better aroma were evenly split between the samples. In terms of flavor, 3 tasters perceived the samples as somewhat similar and 2 felt they were not at all similar. Again, preferences were evenly split. As for mouthfeel, 1 participant found the beers to be identical, 3 thought they were somewhat similar, and 1 taster felt they were not at all similar. The mouthfeel of the Vermont-only beer was preferred by 3 of the 4 tasters who experienced a difference. Overall, 3 of the 5 respondents indicated they preferred the beer fermented with only Vermont Ale yeast.

My Impressions: Knowing there was a difference in SG between these beers, I thought this would be fairly easy. I found it surprising the participants weren’t reliably able to detect what I thought would be a noticeable difference and wondered if perhaps awareness of the SG difference would have contributed to better performance. Surely, with my knowledge of this and the general nature of the xBmt I would be able to tell the difference, right?

Wrong. I triangle tested myself multiple times and consistently selected incorrectly. I really tried on this one, to no avail, I could not reliably distinguish these beers. A BJCP judge friend of mine who experienced similar difficulty on multiple triangle test attempts concluded the differences became more apparent as the beers warmed and lost carbonation. However, my performance was the same regardless of temperature and carbonation level, I just couldn’t tell a difference at all.

| DISCUSSION |

While the results of this xBmt were not statistically significant, I still consider it a success in that my original hypothesis was actually supported– combining Vermont Ale yeast with WLP090 yielded a drier beer, even if by just a couple points, than using the Vermont Ale strain alone without having a significant impact on flavor and aroma. Whether or not it’s worth the effort of combining these yeasts, or if it can even produce a higher quality beer, is still obviously up for debate. But after this experience, I’m comfortable claiming these 2 yeasts can be successfully combined to produce a dry and delicious beer. The fact the Vermont-only batch attenuated as well as it did was completely unexpected, making me wonder what I did to produce results so different from others.

Pitching an attenuative yeast into a beer whose fermentation has stalled isn’t all that novel of a method, but it’s different from the approach discussed in this article in that brewers usually do it as a last ditch effort to save a batch. My interest here was intentionally combining 2 strains based on specific characteristics, which in my opinion opens up a ton of opportunities for creating interesting and potentially incredible beers one couldn’t achieve with a single strain. If you’ve ever blended yeast, intentionally or not, feel free to share your experience in the comments section below!

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| Read More |

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