diacetyl rest before or after lagering

Discussion in 'General Brewing Discussions' started by Ron Reyes (Papa Piggy), Feb 4, 2019.

  1. Ron Reyes (Papa Piggy)

    Ron Reyes (Papa Piggy) Active Member

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    the recipe i am following calls for the rest to take place after lagering? this is my first lager im tempted to just "follow directions" but so many folk do this near the end of Primary. So what's the deal?
     
  2. Nosybear

    Nosybear Well-Known Member

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    Before, in all cases. You want enough yeast in suspension to metabolize the diacetyl, lagering drops most of the yeast out.
     
  3. Ron Reyes (Papa Piggy)

    Ron Reyes (Papa Piggy) Active Member

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    that makes sense. The recipe in question is from a Northern Brewers Kit. I figure they know what they are doing?
     

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  4. ChicoBrewer

    ChicoBrewer Well-Known Member

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    In my experience they do. I have made several and it is a great way to start
     
  5. Nosybear

    Nosybear Well-Known Member

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    Unless they're assuming you don't need a diacetyl rest.... I can see it working at the end but slower, much slower.
     
  6. Ward Chillington

    Ward Chillington Well-Known Member

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    Yes, great way to start and to add to that, those instructions are a great catalyst for more questions. Because of the lack of details, if you are thinking about or concerned with the "how to" steps that are often left out by NB or Midwest, you get pointed at further reading, the distributors chat group or an online forum like this! In chatting with both of these distributors; I have been told that they do that on purpose to account for the different methods that different brewers use.
    Hint: lagering in a carboy vs in the keg or the bottle and back suck.
     
  7. J A

    J A Well-Known Member

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    There's a lot of confusion and "mystique" around the subject of brewing lager-style beers. The process may vary from brewer to brewer but the principles are not all that complex when you break it down:
    - Cooler fermentation generally yields less ester production, but in many yeast strains yields higher diacetyl production.
    - Ester production happens early in the fermentation as a by-product of reproduction.
    - Pitching a much higher yeast cell count limits reproduction and further inhibits ester production.
    - Diacetyl produced at lower temps can be metabolized by yeast when sugar molecules as a food source become more scarce.
    - Raising the temp to encourage yeast metabolism helps to remove diacetyl compounds from the finished beer.
    - Lowering temp after full fermentation forces yeast activity to stop and inactive yeast drops to the bottom of the vessel.
    - As yeast, proteins and other molecules and particulates drop out of suspension, they strip the beer of most remaining flavor compounds.
    - In several weeks time in the low 30s, the beer has cleared about as much as it's going to and improvement is relatively minimal after that.
    - Clearing and settling can happen in the bottle after carbing...there's just a little more yeast sediment at the bottom.
    - Clearing of the beer can be accomplished or assisted by adding floculent or by filtering,
    - All this assumes good sanitation, temperature control and minimal oxygen exposure at all stages of fermentation.
    - Enjoy.
    :)
     
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  8. Iliff Avenue Brewhouse

    Iliff Avenue Brewhouse Well-Known Member

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    In my experience, a diacetyl rest is unnecessary if you pitch enough yeast and have a healthy fermentation. This is also strain dependent though and maybe I just haven't used a strain that produces a lot of diacetyl. Normally, I will taste it to see if it's necessary...
     
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  9. FedoraDave

    FedoraDave Member

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    I've got four lager recipes in my stable, and I've sent three of them to competitions. One won third place in its category, one scored the second-highest I've ever gotten, and the third was a pilsner that didn't do as well as I'd hoped, but is still a nice beer, for what it is. None of the comments I received had any mention of diacetyl.

    From what I've read, a rest should be done at a higher temperature after roughly 75% of fermentation is complete. This means some gravity readings about four or five days after pitching the yeast, and raising the ambient temperature from, say, 52 degrees to around 65 or so. Basically, from lager temps to ale temps. Then, after three days or so, another gravity reading to check if it's getting closer to FG, and then back into the lager temps.

    I also lager the beer after either bottling or racking to a secondary. Several months in the mid-30s. In fact, in early March, I intend to brew my Ottertoberfest so it will be ready to tap in October.
     
  10. Ward Chillington

    Ward Chillington Well-Known Member

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    This has been a real learning batch as I have not done a diacetyl rest before. So here I am in the 11th day and I am at 58F and holding and I have watched my off gassing in the fermentation lock drop from an infrequent large bubble every 45 to 60 seconds between burps to a very small burp every 10 seconds this morning. I understand the frequency correlation as I have increased the tempature but what's behind the volume of gas difference?
     
  11. J A

    J A Well-Known Member

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    CO2 produced during fermentation stays in suspension. The amount that stays is correlated to the temperature - cold beer holds more CO2. Whatever can't stay in suspension gasses off. As you raise temp, more CO2 will be released even if there's been no new fermentation activity for a while. Also, just the difference in the volume of the entire contents of the fermenter increasing as it warms makes less room for the CO2 in the headspace. If you put an airlock on a container of chilled water and allowed it to warm to room temp, it would look as if it's "fermenting" according to bubble activity. And if you poured a commercial beer into a container with an airlock and allowed it to go flat, it would bubble through an airlock, as well.
     
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  12. Ward Chillington

    Ward Chillington Well-Known Member

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    Well the party looks to be over as things, in just a little more than 12 hours, have appeared to stopped. Thanks Yeastie Boyz! Perfect timing for bottling over the weekend.

    Question, for bottle conditioning a lager, do I want to put the bottles in a 70F space for 3 weeks or a lower tempature before they lager for a couple months in the 40F basement cold?
     
  13. J A

    J A Well-Known Member

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    Ideally around 68...70 or higher will do a quicker job of carbing but it's best to avoid temps that are preferred by any stray bacteria that may have found their way in.
     
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  14. Ward Chillington

    Ward Chillington Well-Known Member

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    Thanks J A, I'll just follow the usual botteling protocol
     
  15. Hawkbox

    Hawkbox Well-Known Member

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    Lagering is just clearing the beer as I understand it, so I would do that last. Just store them cool once you've let them carb up.
     
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  16. Ward Chillington

    Ward Chillington Well-Known Member

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    Yuppers Hawk, we're on the same page!
     
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  17. Hawkbox

    Hawkbox Well-Known Member

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    Great minds...
     
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  18. FedoraDave

    FedoraDave Member

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    Sounds like you're on the right track, Ward, and cruising just fine. Should be a real nice beer in a few months.
     
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