Cooling After Diacetyl Rest - 2 Questions

[PistolPatch]

I'm chasing some practical answers on cooling a lager after a diacetyl rest. If I read my New Brewing Lagers book it says for a rest to raise the temp to 13-16 degrees and then after 2 days drop it 3 degrees per day down to 1-3 degrees. Agh! For me and my equipment, this is not practical.

I've had AndrewQLD's pilsner in primary at 10 degrees for 2 weeks. On Saturday, I took it out of the fermenting fridge and the temp has risen to 22 degrees. I've just racked it into a cube and thrown it into my fridge which is set at 2 degrees. My intention was to drop it to ten degrees and hold it there for another week. My questions are...

a) Is what I'm planning OK?
B) Is there a formula to work out (apart from that Newton's Law one which is way too hard) or does anyone know, how long 23 litres in a cube at 2 degrees ambient takes to cool from 22 to 10 degrees? Don't want to wake up in the morning and find it too cold.

Would really appreciate some quick, practical answers as I've had this beer at 22 degrees for an extra day. (Too hungover after Ross's to do it yesterday.)

Cheers
PP
Cooper's BIAB Rep

 

[Coodgee]

what sort of equipment do you have PP? do you have some kind of fridge thermostat that can be set at 10 or 2 degrees? I'm confused. From what I have heard on basic brewing radio, during the lagering period, the yeast is still working down at 2-3 degrees. but only if you don't shock it by cooling too quickly. I would imagine after a good 12 hours in the fridge your beer would come down under 10 degrees. my little bar fridge can do this to 21 litres no worries.
what about a cheap timer from bunnings? that has served me well before the advent of cheap thermostats.

and how hung over were you? you didn't hit the Belgian again did you?

 

[Adamt]

a) Don't ask me

B) Only way to find this out for your particular fridge is experience, or convection heat transfer calculations. I could possibly work out an estimate for you when i get home from work (in abou 5 and a half hours).

Hopefully someone else with a little time has done some heat transfer work before!

-Adam

 

[user 384]

Hi PP

Take NBL with a grain of salt, Noonan can be a bit OTT. Firstly 13C-16C is hardly what I would call a diacetyl rest. 13C is what you would conduct the primary fermentation at for some lager strains!

I remember going to a Wyeast seminar that suggested that over the course of a lager fermentation you should start out at the low end of the temp range, and then over a few weeks slowly raise the temperature to even as high as ale fermentaion temps (I will have to check my notes for the exact recomended time frames and temps). So hitting 22C is not a problem at all. It's in the early stages of a lager fermentation that you want to avoid high temps, the end stages are not as critical.

Also you don't have to be spot on dropping the temp down 3C per day until it hits 1C-3C. The key point is that you reduce the temp again to lager for a period of time.

Don't fret, your beer will be fine, and you don't need any fancier temperature control equipment.

Cheers
MAH

 

[Aussie Claret]

PP,
I think the real question is, is it necessary to drop the temperature over a few days (3 c / day for you would take a week)or is it possible to drop the temperature over a 10-12 hour period? Is this likely to shock the yeast? In my very limited opinion probably not.

Personally and you know I'm also still learning is that I'd drop the temp over night, and that's what I did with my lager we made together. 12 days primary 2 days diactyl rest and a week chilled, it was then kegged last week and has been cc'ing since will leave it a few more weeks, but initial tastes are very good.
Cheers
AC

 

[PistolPatch]

I was just about to post my reply back here to you guys above but as usual, it was atrociously long. I've cut it and will paste it into a PM to each of you now.

One thing I wrote that was nearly on-topic however was to MAH regarding his comments on Noonan. His post above was of great value to me as, at my level, I've found Noonan to be totally bewildering.

Thanks guys for your quick response and I can't wait until Adam gets home - lol!

 

[matti]

PistolPete.
Noonan is very particular and other forums has called him a nit pick.
I suggest that you do a diacethyl rest at 16 degrees for two days or 20 degrees for one day or so.

I prefer the first and it works for me.
Chill it down in lager fridge as per normal. It will take about two day from 16 to 2 degrees pending on fridge.

Here a fool proof method that works for me.
ferment at optimum temp for lager yeast 9-12 degrees.
rack to second when crown receded almost fully into about 10 days reats for 2 days at 16.
allow to ferment out in second and temp will lower it self automatically as activity decreases.
finnished the ferment? bring down to -1 to 2 for 4 weeks .
raise again before bottling or transferring to keg.
matti

 

[Kai]

I remember going to a Wyeast seminar that suggested that over the course of a lager fermentation you should start out at the low end of the temp range, and then over a few weeks slowly raise the temperature to even as high as ale fermentaion temps (I will have to check my notes for the exact recomended time frames and temps). So hitting 22C is not a problem at all. It's in the early stages of a lager fermentation that you want to avoid high temps, the end stages are not as critical.

I do this with all my fermentations if possible, let them raise a few degrees when they are around three-quarters fermented. It seems to help them finish with no ill-effects.

 

[Kai]

And Pete, RDWHAHB. Ferment it at the lager temp, take it out to bring it to room temp for a few days for the rest, bung it back in and turn on the chiller for the lagering. That's all you need.

 

[PistolPatch]

Here a fool proof method that works for me.
1. ferment at optimum temp for lager yeast 9-12 degrees.
2. rack to second when crown receded almost fully into about 10 days
3. rest for 2 days at 16.
4. allow to ferment out in second and temp will lower it self automatically as activity decreases. finnished the ferment?
5. bring down to -1 to 2 for 4 weeks .
6. raise again before bottling or transferring to keg.
matti

Matti, I think that I and many others here just love fool-proof methods. As usual though I might be the fool who asks what are probably very obvious questions. I've put numbers beside your reply above to make my questions easier.

2. I'd imagine that just going 2 weeks would be OK. With my set-up observing the crown/krausen is impossible. Long story.
4. Don't understand the, 'lower itself automatically,' comment fully. My set-up forces the wort to a set temperature, not the ambient. i.e. my wort temperature is fixed. Also, I imagine that here we are aiming to keep it at 9-12.
6. Not sure why you would raise again before kegging?

Many thanks,
PP

 

[AndrewQLD]

Pat,
What you have done in you first post is perfectly acceptable,
1) ferment at 10-12c
2) at or near fermentation completion raise temp to 20-22c for 48 hours.
3) rack to secondary and put in fridge to lower temp to 2-6c, this will take a day or two to drop to that temp anyway.
Don't stress, it's only beer and will turn out fine.

Cheers
Andrew

 

[matti]

AndrewQLD beauty

What i meant with #4 is that:
When activity slows down the temperature generated from the fermentation activity decreases,

The wort will need less fridge POWER to cool down unless you got a fridge-control.

 

[matti]

raise before kegging?

Not sure about that one but a tip i got from a kegger.
Precautious maybe.
No butterscotch flavour in my beer anyway
matti

 

[Coodgee]

can I just ask.. did you actually taste any diacetyl? if you can't taste it then there is no need for these shenanigans. I tend to pitch my lager yeasts reasonably warm (16-18) and this usually prevents the production of diacetyl. The D-rest ranks alongside the protein rest in terms of necessity IMHO (ie, occasionally it might be required, but not usually required).

JMHO, YMMV.

 

[matti]

better be safe then sorry and to answer your question
No i don't recall that

 

[PistolPatch]

What a crack up! Had to do a search for RDWHAHB! I think I blocked this out subconsciously Kai after reading Papazian's book where every second paragraph finished with, 'Relax. Don't Worry. Have a Home Brew." To this day, the espression drives me insane. I wish that he had used it only when appropriate such as you did Kai.

Thanks Kai and others for setting my mind at rest. That lager can just stay in the fridge! Special thanks to AndrewQLD who seems to have a knack to answering my questions in a way I can understand immediately.

Cheers
PP

 

[Guest Lurker]

can I just ask.. did you actually taste any diacetyl? if you can't taste it then there is no need for these shenanigans. I tend to pitch my lager yeasts reasonably warm (16-18) and this usually prevents the production of diacetyl. The D-rest ranks alongside the protein rest in terms of necessity IMHO (ie, occasionally it might be required, but not usually required).

JMHO, YMMV.

I disagree. The precursor to diacetyl can be present, but not tasted. And as soon as you do a transfer, you may well find a pile of it turning up. But if you take a sample, warm it up, oxidise the crap out of it, cant taste any diacetyl, THEN I agree no need for a rest at all.

 

[dubzau]

a related question that somebody might be able to answer!

I've read that it is a common practice among czech brewers to crash the yeast before primary fermentation is completely finished, thus leaving the slight residual sweetness that gives czech lagers their distinctive (and to me pleasing) flavour. The description of Wyeast's Budvar yeast supports this "Flocculates at a warmer temperature (37F) than many lager yeasts, which allows the brewer to more easily leave residual sweetness in the beer".

I know that diacetyl is present in the flavour profile of Urquell, but it is not overpowering and in fact contributes to the complexity of Urquell, and in my experience diacetyl is even less prominent (or absent even) in many other czech pilsners that nevertheless have clear residual sweetness. I tend to find czech pilsners cleaner than many of their european counterparts/immitators.

My question therefore is "professor, why is this so???" What does it say about everything that you've read about lagering (from Noonan and others), that you can crash a yeast a point or two from FG and there is no adverse impact on flavour - and maybe even a positive impact?

I understand the physical effect of lagering - which is that yeast and other particulates settle out gradually leaving a smoother beer (this can of course be greatly hastened by use of clarifiers), but the biological effect is allegedly that the yeast metabolism is slowed, but the yeast continues to work slowly to clean up off flavours produced during primary fermentation. The latter of course would require some active yeast in secondary.

 

[matti]

Mr Bud.
Hate to disappoint you, but you cannot copy a beer like Urquell.
As you said it does have a butterscotch twang in taste and the amount of Saaz hop bittering balance the flavour.

UNLESS you get hold of the unbuffered water of Czech repuplic, No chance.

I made a pilsner with Saaz hop with sydney water adjusted with citric acid to suit the mash and I used 5% caramalt pils and used Noonans tricks in lagering.
Result was a palletable beer that goes well with any Steak you may intake.
Only problem I like Pils better.

I think Oz got the best commercial beers in the entire known Universe and I am trying to find how to make these beer made cheaper.

Now that what this is all about Aye?

 

[warrenlw63]

Take NBL with a grain of salt, Noonan can be a bit OTT. Firstly 13C-16C is hardly what I would call a diacetyl rest. 13C is what you would conduct the primary fermentation at for some lager strains!

PistolPete.
Noonan is very particular and other forums has called him a nit pick.
I suggest that you do a diacethyl rest at 16 degrees for two days or 20 degrees for one day or so.

Saying that Gregory Noonan's OTT and a Nitpick is a little unfair don't you think? He's got a book that's selling it's third reprint and a successful micro. I wouldn't call his advice wrong by any means. :blink:

If you follow his information on a diacetyl rest it will work without a problem and generally speaking being able to re-lower your ferment 1-3 degrees a day is no real stretch with a fridge and proper temp control. OTOH other methods and higher diacetyl rest temps described will work fine too. Basically most methods will clean diacetyl up providing you haven't created too much for the yeast in the first place with things like excessive pitching and primary ferment temps.

It just doesn't seem fair slagging an author of a well-respected book unless you can write one better yourselves.

Look out John Palmer or Ray Daniels you could be next. :lol:

Warren -