Diacetyl Rest

Discussion in 'Homebrewing' started by OldBrewer, Jan 9, 2017.

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  1. OldBrewer

    OldBrewer Maven (1,385) Jan 13, 2016 Canada (ON)

    That is indeed helpful advice. So why do you think that some processes seem to lend themsleves to the presence of diacetyl? How does your process prevent its occurrence? Or is it the type of yeast used, etc.?
     
    #21 OldBrewer, Jan 9, 2017
  2. OldBrewer

    OldBrewer Maven (1,385) Jan 13, 2016 Canada (ON)

    Makes one wonder whether or not judges should be required to be able to detect such things as diacetyl and melanoidin. But then again, tastes vary by so much that it's likely better to have a number of judges rather than just one or two.
     
    #22 OldBrewer, Jan 9, 2017
  3. OldBrewer

    OldBrewer Maven (1,385) Jan 13, 2016 Canada (ON)

    Yes, I mentioned the buttered popcorn taste in an earlier post above. And I can certainly taste the buttered popcorn. But even knowing that taste, I have yet to taste a beer that has that taste. It's possible that I have somehow never yet had a beer with diacetyl in it. I would love to try a beer that has diacetyl just so I will know the taste.
     
    #23 OldBrewer, Jan 9, 2017
  4. JackHorzempa

    JackHorzempa Grand Pooh-Bah (3,375) Dec 15, 2005 Pennsylvania
    Society Pooh-Bah

    I really do not know the answer to your question. I have seen yeast vendors make mention that certain yeast strains are diacetyl 'problem' yeast but I have never personally experienced any issues with these alleged 'problem' yeast strains.
    Again, I really do not know the answer here. I conduct what I consider to be a 'standard' homebrew lagering fermentation/lagering scheme:
    • I ferment at around 50 degrees F for about two weeks.
    • I lager for about 5-6 weeks for my moderate gravity lagers
    I taste the hydrometer sample of the beer after the two week ferment simply as a matter of habit. I have never perceived any diacetyl in those hydrometer samples.
    I have used over half-dozen differing lager yeast strains over the past 15+ years. I would guesstimate about 10 different strains. As I have repeatedly stated: never had a diacetyl issue with any of my lager beers.

    I can simply state my experiences but I need to caveat to you: YMMV.

    Cheers!
     
    #24 JackHorzempa, Jan 9, 2017
  5. GreenKrusty101

    GreenKrusty101 Initiate (0) Dec 4, 2008 Nevada

    Jack,

    I've figured it out...OPDS...(Other People's Diacetyl Syndrome) ...got a touch myself :slight_smile: cheers
     
    #25 GreenKrusty101, Jan 9, 2017
    JackHorzempa likes this.
  6. JackHorzempa

    JackHorzempa Grand Pooh-Bah (3,375) Dec 15, 2005 Pennsylvania
    Society Pooh-Bah

    Barry, believe me if there was perceptible diacetyl in my homebrewed beer I would still taste it and unfortunately for me that would equate to dumping my beer. I am a HUGE non-fan of moderate-high levels of diacetyl in beer.

    There is a brewery near me that until recently (over a year ago) solely produced excellent, high quality beer. A year ago they installed a canning line and they just can't keep up with the absolutely rabid demand for their beers. I have tasted diacetyl in a half-dozen or so batches of their beers in the past year. When it is a draft issue I return it to the bartender and request another beer. When it is a canned beer issue: down the drain it goes. I have no genuine way of knowing what the specific cause(s) are here but I strongly suspect that it is due to production schedule to meet an outrageously strong customer demand thing. In other words they are not permitting sufficient yeast contact time in the fermentors to permit the yeast to 'clean up' after themselves (I think).

    @OldBrewer can state that he has never tasted diacetyl in commercial beer but in the past year I have tasted waaaay to much from a brewery that was heretofore an excellent/outstanding brewery.

    Cheers!
     
    #26 JackHorzempa, Jan 9, 2017
    GreenKrusty101 likes this.
  7. OldBrewer

    OldBrewer Maven (1,385) Jan 13, 2016 Canada (ON)

    Thanks, Jack. You might have come up with the reason for diacetyl in some beers. I know many who keg their beers immediately after fermentation without waiting for the yeast to clean up. I ALWAYS leave my beer on the yeast for a minimum of three weeks before kegging - even ales which have finished fermenting in 4 days. Perhaps the diacetyl rest is only required if one doesn't wish to leave their beer on the yeast for at least 2 or 3 weeks. Perhaps it's more that than the rest that causes the presence of diacetyl.

    As for me not having tasted diacetyl beer in commercial beers, perhaps I have, but as mentioned, I don't really know what that taste is. I do know the taste of buttered popcorn, but I don't recall ever noticing that taste in beers, including my own (I have brewed beer for 25 years).
     
    #27 OldBrewer, Jan 9, 2017
  8. GreenKrusty101

    GreenKrusty101 Initiate (0) Dec 4, 2008 Nevada

    Yes, now that you mention it, I've tasted it in more commercial ales than lagers (commercial and homebrew)...maybe because most brewers fear it more in a lager and take extra precautions?
     
    #28 GreenKrusty101, Jan 9, 2017
  9. GreenKrusty101

    GreenKrusty101 Initiate (0) Dec 4, 2008 Nevada

    I would liken diacetyl more to rancid butter...easy to mistake for stale caramel malts as well as some invert syrups, imho.
     
    #29 GreenKrusty101, Jan 9, 2017
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  10. VikeMan

    VikeMan Grand Pooh-Bah (3,067) Jul 12, 2009 Pennsylvania
    Pooh-Bah

    It can taste that way in high concentrations. But I like the artificial popcorn butter analogy for lower levels, particularly since it's not just an analogy. It's exactly the same compound.
     
    #30 VikeMan, Jan 10, 2017
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  11. GreenKrusty101

    GreenKrusty101 Initiate (0) Dec 4, 2008 Nevada

    As is real rancid butter flavor :slight_smile:
     
    #31 GreenKrusty101, Jan 10, 2017
  12. OldBrewer

    OldBrewer Maven (1,385) Jan 13, 2016 Canada (ON)

    Can you imagine a 'popcorn beer' recipe that uses a lot of corn and makes a real attempt at diacetyl content? Might even be able to soak some actual popcorn in the boil for additional taste. Great for movie-goers!
     
    #32 OldBrewer, Jan 10, 2017
    Last edited: Jan 10, 2017
  13. GreenKrusty101

    GreenKrusty101 Initiate (0) Dec 4, 2008 Nevada

    Full Pint Malt, Flaked Corn, Big "D" English yeast fermented warm, old Carastan and Lyle's Invert Syrup...racked too soon... gonna have to brew it just to see :slight_smile: (not)
     
    #33 GreenKrusty101, Jan 10, 2017
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  14. OldBrewer

    OldBrewer Maven (1,385) Jan 13, 2016 Canada (ON)

    Yes, ferment high, in the keg after 4 days of fermentation. Just watch - someone will try to brew it :slight_smile:
     
    #34 OldBrewer, Jan 10, 2017
    Last edited: Jan 10, 2017
  15. JackHorzempa

    JackHorzempa Grand Pooh-Bah (3,375) Dec 15, 2005 Pennsylvania
    Society Pooh-Bah

    In all fairness a commercial brewer does not have the 'resources' to age ales for 2-3 weeks. Having stated that they should not release beers until they have 'cleaned up' after the final gravity is reached either. I would suggest that a few days post FG is reached may be sufficient. At a minimum, conduct a taste test prior to release like I mentioned in a prior post concerning a local brewpub.

    If as a homebrewer you want to wait 2-3 weeks that is certainly OK. You are not in the business to make money with your beer so you have that latitude.

    Cheers!
     
    #35 JackHorzempa, Jan 10, 2017
    redgorillabreath and OldBrewer like this.
  16. inchrisin

    inchrisin Pooh-Bah (2,013) Sep 25, 2008 Indiana
    Pooh-Bah

    I usually don't tell people to go by their airlock. For a D-rest, I just wait for the airlock to slow way way down and then bump up the temp. Is that 5 points? I dunno. I know I make some decent Kolsches, German Lagers, and Cream ales this way.
     
    #36 inchrisin, Jan 10, 2017
    premierpro likes this.
  17. redgorillabreath

    redgorillabreath Zealot (511) Mar 29, 2015 Pennsylvania

    Definitely in the FWIW category, I'm closing in on having my first Lager under my belt (about a month of lagering left to go). When I did the D-rest the surface of the beer got a little foamy. Could have been more yeast activity, could have been CO2 coming out at the elevated temp. Regardless, I let it "rest" until the surface cleared up.
     
    #37 redgorillabreath, Jan 10, 2017
  18. OldBrewer

    OldBrewer Maven (1,385) Jan 13, 2016 Canada (ON)

    I often go by the bubbles in the airlock, but there are so many variables that it becomes more of an art than a practice. The airlocks, especially on plastic pails are unreliable as often the plastic pail lid will leak slightly, so there is little or no bubbling activity when fermentation slows down. It also depends on how much liquid is in the lock. I often have two identical five-gallon glass carboys side by side, each with half of the wort and yeast, fitted with identical fermentation locks, but the bubbling activity of the two fermentation locks are often significantly different, even though the change in their specific gravities are often similar. The bubbling activity increases to a maximum rate and then begins to slow down. I usually monitor it about a day after it begins to slow down as it's usually about then that the specific gravity is at the point where a rest is recommended.
     
    #38 OldBrewer, Jan 10, 2017
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  19. OldBrewer

    OldBrewer Maven (1,385) Jan 13, 2016 Canada (ON)

    The increase in temperature should also increase the fermentation activity as yeast are generally more active at higher temperatures. When I do the rest, I notice the bubbling activity in the fermentation lock increases a little.

    I'm considering not doing a diacetyl rest anymore since I always leave the beer on the yeast for three weeks anyway, whether ale or lager (I'm not in any hurry). I have a feeling that Jack's onto something when he suggests that rushing a beer into the keg might play a major factor in the presence of diacetyl. A rest is likely not required if you let the yeast do the job of cleaning up the beer. Three weeks might be a little excessive, especially for an ale, but at the same time it doesn't seem to do any harm.
     
    #39 OldBrewer, Jan 10, 2017
    redgorillabreath likes this.
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