Anyone who missed or skipped the discussion with the brewers during the White Labs tour missed a golden learning opportunity. The current brewer and the former brewer fielded questions from attendees. One of my questions verified what I already knew from experience; namely, pitch based on the desired response, not the values that yeast calculators spit out. However, I learned something that I did not know. One of the brewers ferments lagers at 65F under one bar of top pressure using WLP925. I knew about fermenting ales under top pressure, but I had never heard of anyone fermenting lagers at 65F using this method (I need to come out of my cave more often ;D ). Drinkable lager beer can be produced in as little as 10 days using this method. It’s even simpler than Marshall’s method. I do not know how I missed this information because the process is documented on White Labs’ web site.
I haven’t run the data yet on an xBmt you participated in comparing wlp800 fermented at 50 vs 66, no pressure… plan to get it published on Monday-- 40+ participants from NHC!
From what I understand, it’s SOP at many, if not most, of the macro lager breweries.
Edit: As Jeff pointed out, it’s relatively uncommon in smaller breweries simply because fermenters rated to more than ~15 psig are so expensive.
I’ve heard similar, too. Definitely would explain the macros’ ability to crank that stuff out so quickly (and at those volumes).
I’m really looking forward to seeing the results on these. That was one of those where I started to second guess myself since, in some cases, the perceived differences disappear after a little while. I still wonder if something similar happened in Denny and Drew’s experiment. The only perceived difference I had was a slight one in aroma, but since theirs was separated by time, I’m wondering if my receptors for the aroma were just slightly deadened by the time the second beer came along (or if temperature differences were it, etc., etc.).
Jason Pratt from Miller Coors said they ferment at 2 bar! Those are some robust fermenters.
Wow! Robust indeed.
I am looking forward to seeing these results.
+1. I’d like to see something similar done with WLP830, which is known to ferment fairly clean at warmer temps.
The possibilities are endless! 
You do a great job,man !
I just ordered the parts for my spunding valve…
What about the case of fermenting at under one bar? Sean is opening his place and will be fermenting at 0.7 bar due to his 2 mile elevation (Leadville, CO). He tells me that he routinely observes higher than typical attenuation with his ferments at that elevation. I found this to be a curious result.
Perhaps it’s a pressure differential thing where 0.7 bar ~= 1 bar at sea level, similar to how boiling at high elevation happens at lower temperatures. Since the ambient air pressure is lower, maybe 0.7 bar in the fermenter is equivalent.
Looking at the table here, it appears that ambient air pressure is pretty close to that differential at 10,000 feet.
I recently made a Helles at the Green Dragon and the Peltier Chips failed on the chillers. As a result, the WL835 German Lager X fermented out at ~75*F, no pressure. The resulting beer, that I call “Helles?” is surprisingly clean and true to intent. A touch of ester but nothing like I was expecting.
That’s what he’s saying: my ambient air pressure is about 70% of that at sea level. To replicate my fermenter pressure at sea level you’d have to pull a 5 psig vacuum.
Hopefully I’ll have some data on this in the coming weeks/months.
Yep. The first couple years I brewed were on a shoestring college budget, so I brewed in rubbermaid tubs with frozen water bottles for temp control. So I brewed several 2124 lagers managing temps this way. I was surprised how well the beers came out. Not quite like a freezer with a Ranco, but there is some room for error with that yeast.
I suppose I misunderstood what he was saying. I was assuming we were talking about pressurizing to 1 bar above ambient pressure effectively. And that it was going to be a matter of pressurizing to 0.7 bar above ambient instead to get the same effect at higher altitude.
Planning xBmt, need to know if a Dyson will do the trick?
As long as you can seal it to the headspace and have an adjustable VRV I don’t see why it wouldn’t work to pull some vacuum. I’d be kind of surprised if it was able to do 5 psi, but who knows?