The Brülosophy Show: Impact Of PRESSURE FERMENTATION On A Lager (LAB TESTED!) | exBEERiment


Fermenting lager yeast under pressure is purported to lower ester levels when fermenting at ale temperatures, creating a cleaner tasting beer. To test this out, Martin split a German Helles Exportbier between two fermenters and fermented one at 12 psi while the other stayed at ambient pressure. In addition to serving these beers to a panel of blind tasters, they were also sent into White Labs for objective testing. Are they distinguishable at a qualitative and quantitative level? Let’s find out!

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9 thoughts on “The Brülosophy Show: Impact Of PRESSURE FERMENTATION On A Lager (LAB TESTED!) | exBEERiment”

  1. Wonder how my go-to pressure fermented yeast, W 34/78, would have performed? Or do we accept this experiment’s results for all lager yeasts ? If not, could you repeat the experiment using the very more commonly used 34/78?
    Also noted the traditional boil time of 90 minutes was replaced with a 30 minute boil. I was considering dropping my 90 minute Pilsner boil to 60 minutes. After watching this video, I will certainly drop it to 60 minutes. Saves me half an hour!
    Thanks.

  2. Awesome experiment, I just wish yours were written up instead of video format.

    I’m curious what’s in this Mythical Hammer blend. It seems like maybe it’s similar to 34/70 where Fermentis already showed quantitatively that it works cleanly at ale temperatures yet people ferment with it under pressure anyway convinced that it makes the product cleaner still (or are convinced that it isn’t clean at ale temperatures).

      1. It’s already pretty fast when fermenting in the 16-19C range (faster than US05, but slower than S04). I suppose it might get faster still at an even higher temperature. Fermentation under pressure results in already carbonated beer so there’s that.

  3. We’ve been fermenting all our lagers under pressure for the past year and the results have been amazing. The only noticeable difference is the cloudiness after it’s conditioned, but it eventually drops out within a day or two under pressure on the taps. Great review Martin!

    PS. We’ve pressurized as high as 15 psi and at 72-75F with no negative effects.

  4. This doesn’t impact the experiment and is just a fun fact, but:

    Am I the only one who noticed that we have 2 beers with the same starting gravity (same wort), 2 different final gravities, but that the one with the lowest attenuation has higher ABV????
    That means that either the worts were a bit different or that the differences in analysis were within error of measurement.
    It would be interesting if whitelab gave some interval of confidence with the analysis.

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