Pils needs diacetyl rest but ...

[meesterparker]

Hey
So my Pils is in day 9 and at 1.01-1.012, and is nearing rest stage. I've got a Saison aging as well as a stout in the chamber. If I raise my temps up, will these beers be affected? I have fine tuned those 2 over a few batches and don't want to throw them off.

Other option is bringing Pils in house for 2-3 days.

Thoughts???
Thanks

 

[Dland]

I'd bring it in the house and let the other beer stay cool, but probably would not hurt much to raise them to mid 60sF for a few days either.

 

[couchsending]

Does your pils need a diacetyl rest? Does it have diacetyl? Never done a diacetyl rest with a lager, never had diacetyl....

 

[meesterparker]

Does your pils need a diacetyl rest? Does it have diacetyl? Never done a diacetyl rest with a lager, never had diacetyl....

Brought inside, used a heat belt to get it up to where I wanted it. Totally forgot I had those bad boys.

 

[cactusgarrett]

At 1.010-1.012, you're probably past the point of benefit from a bump in temp. Unless, that is, you're expecting to get down to 1.005 or so. Without knowing what your OG was, the d-rest is best done with about 25% of attenuation left to help the yeast finish the batch off - have it gain momentum to plow over that last hump, so to speak.

For example, if you started at 1.055 and expected to get an FG of 1.010 (45 point drop), you'd start the rest around 1.021. (75% of 45 points = 34 points, 1.055-1.034 = 1.021)

BUT! As couchsending alluded to, you may not even have needed one if you didn't detect it in the first place. D is often avoided with a healthy ferment.

 

[meesterparker]

At 1.010-1.012, you're probably past the point of benefit from a bump in temp. Unless, that is, you're expecting to get down to 1.005 or so. Without knowing what your OG was, the d-rest is best done with about 25% of attenuation left to help the yeast finish the batch off - have it gain momentum to plow over that last hump, so to speak.

For example, if you started at 1.055 and expected to get an FG of 1.010 (45 point drop), you'd start the rest around 1.021. (75% of 45 points = 34 points, 1.055-1.034 = 1.021)

BUT! As couchsending alluded to, you may not even have needed one if you didn't detect it in the first place. D is often avoided with a healthy ferment.

Good to know. Only 2nd time doing a Pils, so still fine-tuning. Thanks for the tip.

 

[cactusgarrett]

Good to know. Only 2nd time doing a Pils, so still fine-tuning. Thanks for the tip.

Sure thing. EVERY beer has potential for diacetyl, but it's more typically observed in lagers since the yeast have a harder time and ale yeast tend to be more "flavor expressive", potentially masking diacetyl better, if present. Bottom line - treat your yeast right (big starters, proper pitch rate) and you shouldn't have to worry about The D.

 

[FatDragon]

The other thing is that temperature is generally only a major issue for the first couple days of a ferment. Lagers may be a bit more finicky, but most flavor contributions (good or bad) from ale yeast are locked down in the first couple days of fermentation. After that point, you don't want to go wild but it rarely hurts anything to bump the temp a few degrees, and indeed it's often beneficial.

 

[mongoose33]

One thing I've come to understand about brewing is that not everyone can detect all the flavors, off-flavors and otherwise.

So if one can't detect diacetyl, does that mean it's not there, or does it mean one can't detect it?

It also may depend on the degree of that flavor, minor amounts may not be apparent to some people, while others pick up on it.

I've come to the place in my brewing where i do a rest for everything, whether it's ales or lagers. Let the yeast clean up. Typically with ales, whose ferm temps are usually in the low-to-mid 60s, I'll bump up the temp to 71 when the krausen has fallen. That's similar to what @cactusgarrett suggests above, i.e., the yeast are still active but slowing down.

With lagers I ferment at 50, then using a fast-lagering schedule, at 50 percent attenuation I bump the temp up 4 degrees every 12 hours until 66 degrees, then hold it there until finished, then go down 6 degrees every 12 hours.

Lots of ways to kill this cat, this just happens to be how I do it.

 

[meesterparker]

One thing I've come to understand about brewing is that not everyone can detect all the flavors, off-flavors and otherwise.

So if one can't detect diacetyl, does that mean it's not there, or does it mean one can't detect it?

It also may depend on the degree of that flavor, minor amounts may not be apparent to some people, while others pick up on it.

I've come to the place in my brewing where i do a rest for everything, whether it's ales or lagers. Let the yeast clean up. Typically with ales, whose ferm temps are usually in the low-to-mid 60s, I'll bump up the temp to 71 when the krausen has fallen. That's similar to what @cactusgarrett suggests above, i.e., the yeast are still active but slowing down.

With lagers I ferment at 50, then using a fast-lagering schedule, at 50 percent attenuation I bump the temp up 4 degrees every 12 hours until 66 degrees, then hold it there until finished, then go down 6 degrees every 12 hours.

Lots of ways to kill this cat, this just happens to be how I do it.

Beauty. Thanks. I am in that boat where I can identify off flavours, but can't always put the flavour to the label....know what I mean?

Great advice...

 

[Duffman870727]

D is often avoided with a healthy ferment.

Diacetyl is always produced by yeast, healthy yeast will re-uptake it and break it down, unhealthy yeast will not. Some strains (particularly some fast-floccing English) will simply go dormant before fully cleaning up.

So if one can't detect diacetyl, does that mean it's not there, or does it mean one can't detect it?

Could go either way, you'd really have to know your personal palate to make that call. In sensory training, I completely failed the diacetyl test. When handed the bottle of concentrated D afterwards, taking a straight whiff all I could smell was vinegar. I am part of the population that is completely blind to diacetyl, but that doesn't mean it's not there if I don't detect it.

 

[mongoose33]

Could go either way, you'd really have to know your personal palate to make that call. In sensory training, I completely failed the diacetyl test. When handed the bottle of concentrated D afterwards, taking a straight whiff all I could smell was vinegar. I am part of the population that is completely blind to diacetyl, but that doesn't mean it's not there if I don't detect it.

I don't have the world's greatest palate either. I took an off-flavor workshop last summer and it's...interesting trying to decide what "flavor" something is.

This is slightly tangential, but I have a feeling you understand it better than some others: it's very common here on HBT for someone to disagree about a process, saying something to the effect of "I did that and I didn't detect any XXXX" or "I did that and it worked just fine for me."

Well. Maybe. I don't doubt that they didn't detect something, or that it "worked" for them....but how much of that is being unable to detect something? It's made me less willing to take some of what I read here at face value. Not that someone is lying--I don't think that at all. And I don't disbelieve them when they say they didn't detect something, or a particular process had no negative effects.

But is it true, or is it just they didn't/can't notice it?

Who knows?

*****

I've got a friend here, beer drinker, with a a tremendous palate. I give him my beer on a semi-regular basis for his opinion, and of course, what I'm trying to see is if he can detect off flavors. I'm pretty sure my process is good, but I want verification from someone who can taste some of these subtleties better than I can.

 

[Hopalong]

Omitted from home brew info about diacetyl is that krausening is needed to ensure there's enough yeast to finish secondary fermentation and to carbonate the beer during conditioning. It's better to clean up the brewing method than to use a diacetyl rest. The rest is a temporary patch because diacetyl returns and it becomes stronger the longer the beer is stored.

 

[FatDragon]

Omitted from home brew info about diacetyl is that krausening is needed to ensure there's enough yeast to finish secondary fermentation and to carbonate the beer during conditioning. It's better to clean up the brewing method than to use a diacetyl rest. The rest is a temporary patch because diacetyl returns and it becomes stronger the longer the beer is stored.

Fortunately, I can use my several-months-old flat homebrew to butter my popcorn because of all of the delicious diacetyl it's developed in the meantime.

 

[cactusgarrett]

Omitted from home brew info about diacetyl is that krausening is needed to ensure there's enough yeast to finish secondary fermentation and to carbonate the beer during conditioning. It's better to clean up the brewing method than to use a diacetyl rest. The rest is a temporary patch because diacetyl returns and it becomes stronger the longer the beer is stored.

I wouldn't rely on the word "needed". You'd probably be hard pressed to find a significant number of brewers here that Krausen, and I don't think diacetyl is running rampant in all the beers that are being bottle conditioned without re-yeasting.

Could you elaborate on your comment that "diacetyl returns and becomes stronger the longer the beer is stored"? Logic would dictate that since diacetyl is a byproduct of fermentation, and it's there because the yeast didn't re-metabolize it during the stationary phase, the levels should top out shortly after fermentation (ie. conditioning in the bottle) has finished and the yeast has gone dormant. Why would diacetyl return after the yeast have gone dormant and stopped producing then scrubbing it? I'm not seeing a mention of this increase in d after bottling in any of the reference material I've looked at.

It's better to clean up the brewing method

I am on the same page as you on this one. If I had to pick between making a starter and pitching the "right" amount of healthy yeast versus doing a d-rest, i would rely on the starter every time. That d-rest is just an easy, free insurance policy, though.

 

[Vale71]

Could you elaborate on your comment that "diacetyl returns and becomes stronger the longer the beer is stored"?

The guy is just trolling the forum and spouting nonsense. Pay him no attention whatsover.

 

[Duffman870727]

but how much of that is being unable to detect something? It's made me less willing to take some of what I read here at face value. Not that someone is lying--I don't think that at all. And I don't disbelieve them when they say they didn't detect something, or a particular process had no negative effects.

But is it true, or is it just they didn't/can't notice it?

Everybody has a different palate, and is more or less sensitive to certain compounds than the next person. Much of this is genetic, some of it is ignorance due to lack of training/experience. You need exposure to something and a definitive statement of what that characteristic is to be able to associate it to a "flavor". Entry level sensory training is exposure to high concentration compounds so there is no mistaking the presence, it is "yep, that's there and this is what it is". They are typically very low level in most actual beer unless it is severely flawed. If many people agree that a certain process has no noticeable negative effects, chances are the assessment is accurate, though there may be a few super sensitive people that can pick up a subtle effect from the process.

Why would diacetyl return after the yeast have gone dormant and stopped producing then scrubbing it? I'm not seeing a mention of this increase in d after bottling in any of the reference material I've looked at.

I am on the same page as you on this one. If I had to pick between making a starter and pitching the "right" amount of healthy yeast versus doing a d-rest, i would rely on the starter every time. That d-rest is just an easy, free insurance policy, though.

Diacetyl after packaging can occur, but is a sign of contamination (pediococcus).

Don't have time to get into my reference material, but allowing the ferment temp to rise a few degrees at around 70% attenuation simply helps the yeast clean up more VDK, and faster, than maintaining a steady cold. Although lager yeast can work cold, all yeast prefer to be warm. A steady cold ferment will eventually clean up the diacetyl, just not as completely as if it were allowed to warm up for a d-rest. Perhaps it is below your sensory threshold to skip the d-rest, I know it's certainly below mine! I'm D blind!

 

[mediant]

• Yeast do not produce diacetyl - they produce α‐acetolactate
• Yeast do not need D-rest to reduce diacetyl, D-rest is needed to facilitate α‐acetolactate decarboxylation into diacetyl
• Yeast do not metabolize α‐acetolactate, so one must wait until all α‐acetolactate is trasformed into diacetyl (forced diacetyl test)
• Without D-rest or when cold crashed too early, α‐acetolactate will convert to diacetyl anyway later, but there'll be no yeast to reduce it

P.S. Infection may be the most common cause of diacetyl in homebrew.

 

[cactusgarrett]

Diacetyl after packaging can occur, but is a sign of contamination (pediococcus).

Don't have time to get into my reference material, but allowing the ferment temp to rise a few degrees at around 70% attenuation simply helps the yeast clean up more VDK, and faster, than maintaining a steady cold. Although lager yeast can work cold, all yeast prefer to be warm.

Yeah, i'm on the same page as you for the rest and how to do it. I just wanted clarification on the bottling part, as it seemed like we were discussing "normal" circumstances with conditioning via yeast and the typical yeast metabolic pathway, not that contamination was on the discussion table. THAT part i was aware of, also.

 

[mongoose33]

Everybody has a different palate, and is more or less sensitive to certain compounds than the next person. Much of this is genetic, some of it is ignorance due to lack of training/experience. You need exposure to something and a definitive statement of what that characteristic is to be able to associate it to a "flavor". Entry level sensory training is exposure to high concentration compounds so there is no mistaking the presence, it is "yep, that's there and this is what it is". They are typically very low level in most actual beer unless it is severely flawed. If many people agree that a certain process has no noticeable negative effects, chances are the assessment is accurate, though there may be a few super sensitive people that can pick up a subtle effect from the process..

I think you may have missed my point. All the above is true--I've taken a workshop on off-flavors--but that's not what I was pointing out.

It's that when someone online here says they did some process change or recipe tweak and it didn't produce "X" or "Y" off-flavor outcome, is it that "X" or "Y" weren't produced, or is it that they can't detect that it did?

And thus, when that someone reports their results, are we seeing evidence that a process or recipe worked, or just evidence of a palate that can't detect it?