Author Topic: timing a lager D-rest  (Read 2689 times)

Offline wort-h.o.g.

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timing a lager D-rest
« on: May 17, 2013, 06:28:29 AM »
Started brewing lagers about 4 months ago - so very new to it. Im trying to figure out how and when to perform the diacetyl rest. its my understanding all lagers will produce diacetyl - how much depends on temp, yeast, etc, and how much you personally detect in smell or taste depends upon your sensitivity to diacetyl. for me personally, i can detect the taste or smell even in small amounts - and even if the slick feeling people describe isn't present. Ive read people letting the lager finish up at about 2 weeks, and then let it rise to about 60F. i'm somewhat curious about this practice, as my understanding is by that point fermentation is completed and would seem there's not as much yeast in suspension that are active enough to clean up diacetyl (??).

I currently have a 1.052 pilsner and 1.053 vienna lager that have been fermenting for 6 days at 49-50F (i pitched yeast at 48F wort). the krausen has dropped and is starting to settle. i really don't want to pull the airlock and release the co2 to take a hydrometer reading - so wondering if there's a method anyone uses to determine when to do the d-rest? i'm leaning towards waiting for krausen to drop, and then around day 10 let the temp rise to about 60F for 48 hours or burnout, then slowly bring it down to 45F before lagering - -thoughts??
« Last Edit: May 17, 2013, 06:31:09 AM by wort-h.o.g. »

Offline klickitat jim

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Re: timing a lager D-rest
« Reply #1 on: May 17, 2013, 06:34:42 AM »
I'm new too but no D yet. I run at 50 till I drop below 1.020 which I test around 7-10 days in. Once below 1.020 I walk it up to 60 for a few days. When my FG is reached I do a day at 68, boil point for D. Then drop to lager temp.

Offline davidgzach

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Re: timing a lager D-rest
« Reply #2 on: May 17, 2013, 06:39:34 AM »
Everything above looks correct except that "all lagers will produce diacetyl".  Not all strains will produce diacetyl and it will mainly depend upon whether you pitch the correct amount of yeast and the fermentation temperature.

That aside, your plan is sound.  IMHO, a D-Rest is mainly insurance if you pitched and fermented correctly.  You may not need one at all, but it will not hurt your beer either. 

I typically wait until I see little to no activity and then raise it up(given an active fermentation).  Others have different processes.  This works for me without having to take numerous gravity readings.

Dave

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Offline wort-h.o.g.

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Re: timing a lager D-rest
« Reply #3 on: May 17, 2013, 06:42:43 AM »
Everything above looks correct except that "all lagers will produce diacetyl".  Not all strains will produce diacetyl and it will mainly depend upon whether you pitch the correct amount of yeast and the fermentation temperature.

That aside, your plan is sound.  IMHO, a D-Rest is mainly insurance if you pitched and fermented correctly.  You may not need one at all, but it will not hurt your beer either. 

I typically wait until I see little to no activity and then raise it up(given an active fermentation).  Others have different processes.  This works for me without having to take numerous gravity readings.

Dave

Maybe someone else can weigh in, but seems to me diacetyl is always produced - just at different levels??

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Re: timing a lager D-rest
« Reply #4 on: May 17, 2013, 06:43:02 AM »
I wouldn't worry about pulling the airlock to take a gravity reading.  It's still fermenting and producing CO2.  Wait until its 4 or 5 points above your projected final gravity and ramp it up.

Although I usually don't bother taking a reading anymore since I usually just wait until it visually starts to look like it's getting towards the end and then ramp it up. 

I tend to do a D-rest on all of my lagers even though it's not strictly necessary just to be on the safe side and to ensure it attenuates all the way.
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Offline davidgzach

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Re: timing a lager D-rest
« Reply #5 on: May 17, 2013, 06:53:06 AM »
Everything above looks correct except that "all lagers will produce diacetyl".  Not all strains will produce diacetyl and it will mainly depend upon whether you pitch the correct amount of yeast and the fermentation temperature.

That aside, your plan is sound.  IMHO, a D-Rest is mainly insurance if you pitched and fermented correctly.  You may not need one at all, but it will not hurt your beer either. 

I typically wait until I see little to no activity and then raise it up(given an active fermentation).  Others have different processes.  This works for me without having to take numerous gravity readings.

Dave

Maybe someone else can weigh in, but seems to me diacetyl is always produced - just at different levels??

Yes, misstated.  It is always produced but a healthy fermentation will allow the yeast to re-absorb it before FG, some better than others.  Definitely at different levels.

Dave 
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Re: timing a lager D-rest
« Reply #6 on: May 17, 2013, 06:54:32 AM »
If you pitch enough healthy yeast, pitch slightly cooler than ferment temps, and maintain a constant, steady temp in the 48-52F range for 3-4 weeks (allowing the yeast to reabsorb fermentation by-products), then a D-rest isn't needed IMHO.

I make plenty of lagers and I am sensitive to diacetyl and I have never found diacetyl in my lagers post fermentation. 

Just my opinion.

Offline theDarkSide

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Re: timing a lager D-rest
« Reply #7 on: May 17, 2013, 06:56:07 AM »
I pitch cold (45F) and let it free rise and hold at 50F.  Near the end of fermentation, I may raise it 5 degrees or so for a couple days.  I am a believer if you pitch cold, diacetyl is minimized, requiring only a minimal D-rest. 

I've done about 6 lagers, entered a few of them in several competitions and never got any feedback regarding diacetyl.

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Offline wort-h.o.g.

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Re: timing a lager D-rest
« Reply #8 on: May 17, 2013, 06:57:42 AM »
Everything above looks correct except that "all lagers will produce diacetyl".  Not all strains will produce diacetyl and it will mainly depend upon whether you pitch the correct amount of yeast and the fermentation temperature.

That aside, your plan is sound.  IMHO, a D-Rest is mainly insurance if you pitched and fermented correctly.  You may not need one at all, but it will not hurt your beer either. 

I typically wait until I see little to no activity and then raise it up(given an active fermentation).  Others have different processes.  This works for me without having to take numerous gravity readings.

Dave

Maybe someone else can weigh in, but seems to me diacetyl is always produced - just at different levels??

Yes, misstated.  It is always produced but a healthy fermentation will allow the yeast to re-absorb it before FG, some better than others.  Definitely at different levels.

Dave

understood.  I'm generally opposed to popping the airlock and taking a reading - i've proved out i can trust my process and fermentation always takes off (within 12 hours for ales, 12-18 hours for lagers) for ales and lagers alike, and finishes up as expected. i pitch appropriate quantities of yeast, and always use oxygen.

Offline davidgzach

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Re: timing a lager D-rest
« Reply #9 on: May 17, 2013, 06:59:30 AM »
^^^^^^^Sounds good.  I would go with your plan.

Dave
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Offline udubdawg

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Re: timing a lager D-rest
« Reply #10 on: May 17, 2013, 07:27:33 AM »
with "normal" size lagers it is always somewhere in the day 5-7 range for me.  6 being the most common.  I understand not wanting to open it to take a reading, but there is something to be said for understanding your whole process.  I rarely check gravity anymore, because I used to, and now know "when I see this, I raise the temp"

...I suspect it is ready for the d-rest, ignoring whether it even needs one.

good luck--
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Offline wort-h.o.g.

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Re: timing a lager D-rest
« Reply #11 on: May 17, 2013, 08:00:39 AM »
with "normal" size lagers it is always somewhere in the day 5-7 range for me.  6 being the most common.  I understand not wanting to open it to take a reading, but there is something to be said for understanding your whole process.  I rarely check gravity anymore, because I used to, and now know "when I see this, I raise the temp"

...I suspect it is ready for the d-rest, ignoring whether it even needs one.

good luck--
--Michael

i agree . ive noticed a repeatable pattern in time it takes the start of fermentation and time it starts winding down. i also pitch 45-48F, plenty of yeast, oxygen.  for 1.045-1.055, they generally take off at around 18 hours (+- 4) and noticeable activity finishing up around day 7-10. that's when i'm likely to let it rise on its own to around 60F.

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Re: timing a lager D-rest
« Reply #12 on: May 17, 2013, 08:56:43 AM »
Everything above looks correct except that "all lagers will produce diacetyl".  Not all strains will produce diacetyl and it will mainly depend upon whether you pitch the correct amount of yeast and the fermentation temperature.

That aside, your plan is sound.  IMHO, a D-Rest is mainly insurance if you pitched and fermented correctly.  You may not need one at all, but it will not hurt your beer either. 

I typically wait until I see little to no activity and then raise it up(given an active fermentation).  Others have different processes.  This works for me without having to take numerous gravity readings.

Dave

Maybe someone else can weigh in, but seems to me diacetyl is always produced - just at different levels??

Diacetyl is always produced AFAIK but some yeasts are better at getting rid of it than others.  I don't think I've ever needed a diacetyl rest with WY2206.  Same with 2124 now that I think about it.  If I don't smell or taste diacetyl, I don't bother with a rest. 
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Offline theDarkSide

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Re: timing a lager D-rest
« Reply #13 on: May 17, 2013, 09:01:06 AM »
Diacetyl is always produced AFAIK but some yeasts are better at getting rid of it than others.  I don't think I've ever needed a diacetyl rest with WY2206.  Same with 2124 now that I think about it.  If I don't smell or taste diacetyl, I don't bother with a rest.

I use 2124 (or WLP830) for all my lagers...maybe that's why I never have any issue.
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Offline wort-h.o.g.

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Re: timing a lager D-rest
« Reply #14 on: May 17, 2013, 10:43:28 AM »
good info from everyone. seems like we are all on the same page. it just seemed odd to me to hear people do a d-rest after 2 weeks at 50F...seems all activity would be done and there would be nothing gained from doing a d-rest then (considering a normal lager range around 1.050-055). maybe for bigger beers over 1.060 there would still be fermentation activity near the 2 week mark - i just haven't done a lager that big.