diacetyl rest - such thing as too long?

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kokonutz

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Hi - I've been working at my first lager...I pitched at 10.5C (51F) and chambered at that temp for 8 days. Then I pulled out the vessel and raised the temp for a D-rest around 19C(66F), intending just a couple days. Life got in the way, and it's been a week at D-rest temp. (14 days total since pitching) - My intended keg for the lager is still being used, which has me wondering if I need to bottle off what's left in that keg to get this guy layered, or just not worry about it since I'm way past 2 days. Is there a consequence to consider in a long D-rest? I have not tried it and don't really want to open the vessel unless it's my best indicator of next steps.
 

jdauria

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It will be fine...my lagers, which I brew a lot of, sit in primary fermenter for at least 3 weeks, thought I do start bringing temp down 2 degrees a day after D-Rest. If you have space, you could always cold crash it in the fermenter, in your fridge/kegerator. 2-3 weeks sitting on yeast is not an issue either, as you really need to go longer than before extended time on the yeast can cause issues.
 

Spartan1979

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My lagers usually spend 7-10 days at a D rest temp. You're fine.

I haven't gone much past that so I can't tell you if you should go ahead and bottle or not. A couple of more days shouldn't hurt.
 

Nate R

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Am i off base- is the 8 days too short before the d-rest? I would assume with the lager yeast you would want 14 to 28 days before you start d-rest?
Given the 8 days, i think the extra time at d-rest temp may actually be good for the beer.
I must be missing something here... not much help to the O.P., other than i agree it should be fine.
 

Qhrumphf

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With lagers I find its best to do things 100% by gravity and sensory, never by timeframe. Ramp to diacetyl rest when it's still fermenting and like 80% of the way to target (ex: if your OG is 1.050 and your expected FG is 1.010 let it free rise up at 1.020). With a healthy proper pitch rate and oxygenation yeah you should be ramping up within a week. And then it might take a week or more to fully clear the diacetyl precursors (which have way higher sensory threshold than diacetyl -ie you're not gonna taste em- but will oxidize to diacetyl, this is why the forced test is important).
 

dmtaylor

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I often do diacetyl rests for 3-4 weeks. If you miss the timing and the yeast is mostly settled out before you initiate the rest, in my experience it will often take this long for residual yeast to eat the diacetyl. No worries. The beer will still clean up and taste great in the end.
 

bannonb

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The book Brewing Better Beer by Gordon Strong describes primary at yeast temp until within a few points of final, then let it rise to something around 10 degrees higher for the d-rest. He suggests an equivalent time to the primary fermentation. I am brewing a pils now on day 5 of primary, still at 1.019, but bubbling away and smelling like sulphur. All is well!

Point being for primary, you really have to watch the SG to know when to pull the trigger on the d-rest (as said earlier). The Tilt Hydrometer is great, no waste, no muss, no fuss and total visibility. The duration of the d-rest should be reasonable in my humble opinion (a week). Then I like to rack to a secondary vessel for lagering and ramp down a couple of degrees per day for a while, then drop to 33 and let the clock begin (4-6 weeks is my choice).
 

Immocles

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With lagers I find its best to do things 100% by gravity and sensory, never by timeframe. Ramp to diacetyl rest when it's still fermenting and like 80% of the way to target (ex: if your OG is 1.050 and your expected FG is 1.010 let it free rise up at 1.020). With a healthy proper pitch rate and oxygenation yeah you should be ramping up within a week. And then it might take a week or more to fully clear the diacetyl precursors (which have way higher sensory threshold than diacetyl -ie you're not gonna taste em- but will oxidize to diacetyl, this is why the forced test is important).
I hate asking this since it’s probably painful obvious, but what exactly is “free rise”? I’ve seen it and always just glossed over it.
 

Immocles

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Let it climb in temp on its own without actively heating it. Simple as that.
Makes sense. I had a feeling it was something along those lines. Is adding heat vs free rising detrimental in any way? I ask because I ferment my lagers seasonally, in a cold basement, and am forced to use heat.
 

Immocles

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Hmm, so maybe I fell ass-backwards into the correct procedure. This is only the second winter I've fermented lagers, and I've actually had decent luck thus far. Last year I sorta guessed when the airlock and krausen was slowing up and would ramp up about 1F every 8-12 hours until I hit about 65-67 (ferment at 50-52) and leave it there about a week. This year, I have a tilt to help the timing, but still using the same ramp up schedule.

Thanks for the responses. Sorry to hijack a thread!
 

Bobby_M

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Am i off base- is the 8 days too short before the d-rest? I would assume with the lager yeast you would want 14 to 28 days before you start d-rest?
Given the 8 days, i think the extra time at d-rest temp may actually be good for the beer.
I must be missing something here... not much help to the O.P., other than i agree it should be fine.
Since you should D-rest before the yeast floc out, you need to do it with some remaining fermentation needed. For me that is usually about day 7-10 after pitching for mid gravity lagers. If you don't reach that point for more than two weeks, either your pitch rate or fermentation temperature is woefully too low.
 

renstyle

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I currently have a brown ale in my FC.

Started at 1.051 6 full days ago.
Current SG is 1.022 @ 65F/18.5C, where it's been sitting (within a degree up or down) the entire time.
Heading for a 1.014 FG.

I realize lagers and other "lighter" beers benefit greatly from a d-rest, but I'd like to try one with this batch.

Anybody tried this? The FC is inkbird controlled. It's too cold in my place for "free rise", so where would you suggest I gently increment up to? 68F/20C? Maybe 70F/21.5C?

Should I keep the temp up until fermentation is complete?

I'm asking now as the ferm is not finished, but wasn't sure if my batch is far enuf along.
 

dmtaylor

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I currently have a brown ale in my FC.

Started at 1.051 6 full days ago.
Current SG is 1.022 @ 65F/18.5C, where it's been sitting (within a degree up or down) the entire time.
Heading for a 1.014 FG.

I realize lagers and other "lighter" beers benefit greatly from a d-rest, but I'd like to try one with this batch.

Anybody tried this? The FC is inkbird controlled. It's too cold in my place for "free rise", so where would you suggest I gently increment up to? 68F/20C? Maybe 70F/21.5C?

Should I keep the temp up until fermentation is complete?

I'm asking now as the ferm is not finished, but wasn't sure if my batch is far enuf along.
Hit it with 70F/21C for the next 4 or 5 days. Right now, right this second, is the ideal time to raise the temperature.
 

renstyle

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I'm using a 12W reptile heat pad in the FC, so it takes a while to ramp the temp up. She was at 18.0C this morning. Gonna be out of town this weekend, so will check the gravity next Monday and likely xfer to serving keg for cold crashing. I have carb caps now, so looking forward to playing with gelatin injection, oxygen free. LOL

The Inkbird is set to 21C/70F now. Thanks!
 
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