National Homebrew Club Ireland

General Discussions => Chit Chat => Topic started by: Donny on June 03, 2017, 10:02:04 PM

Title: Lagering Questions
Post by: Donny on June 03, 2017, 10:02:04 PM
Can anyone tell me if there is any advantage in just dropping the temp for lagering straight away over stepping it down slowly over a few days?

Has anyone ever done a comparison and noted any differences between them?
Title: Re: Lagering Questions
Post by: DEMPSEY on June 03, 2017, 10:37:55 PM
By dropping it slowly you allow the yeast to continue its job where as a quick crash can stop the yeast in its tracks.
Title: Re: Lagering Questions
Post by: Gerryjo on June 03, 2017, 11:39:04 PM
Does anybody have a light lager recipe similar to Coors as I've just sorted my fermentation fridge and I'm looking to brew one for my wife.Any info is greatly appreciated.

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Title: Re: Lagering Questions
Post by: sub82 on June 04, 2017, 07:07:54 AM
Haven't tried it myself but Brülosophy has a 'quick' method.

Lager Method (http://brulosophy.com/methods/lager-method/)
Title: Re: Lagering Questions
Post by: mr hoppy on June 04, 2017, 10:33:47 AM
I did this recently using a fast lager technique. More Corona than Coors (Coors would have rice instead of flaked corn) and my efficiency was higher than expected so the ABV was higher than expected also.

If I was trying to do this with rice I'd consider using something like this in the recipe below

http://spices.com.mt/index.php/rice-flours/rice/east-end-flaked-rice-powa-medium-1kg.html

Mash ingredients:
5g CaCh
5g Gypsum
2.8kg MCI lager malt
0.07kg Acid malt
0.5kg Vienna
0.13kg Melanoiden malt
0.6kg Corn flakes

Single infusion mash at 65C

90 minute boil

25g Hallertau Mittelfruh 2.9% AA FWH
25g  Hallertau Mittelfruh 2.9% AA 30 mins
20g  Hallertau Mittelfruh 2.9% AA 5 mins

OG 1052
FG 1010
IBU 21
ABV 5.5

WLP 940 Mexican Lager yeast

The yeast was past its best before so I did a two step starter with a stir plate and a 5l flask with this pitch calculator.

http://www.brewunited.com/yeast_calculator.php

The first step was 1l which I chilled for 36 hours when done. After chilling I decanted the wort and added 2.1l of fresh wort. When this was done I chilled again and decanted before adding to the main batch. This technique maximises yeast growth in the starter and minimises it in the final beer. I think this made a huge difference to the finished product. The downside of a two-step starter is you need to begin your starter 5 days before the brew day.

I fermented in a fridge with a STC for temp control.

I pitched at 17C (not ideal) after aerating with unfiltered air for about an hour (again not great) but dropped it to 11.5C after 3 hours.

After 4 days I checked the gravity which was down to 1030 (i.e. half way to expected terminal gravity) at 12.3C I started raising the temp by 1.5C two times daily, reaching 20C in 3 days. I held it at 20C for two days and checked gravity which was 1010. I checked again after two days and it was still 1010 so I cold crashed down to -1C, monitoring to make sure that the air lock content didn't get sucked back in. All this was in the primary and I racked it to a keg after another 9 days. 

The idea here being to get the yeast to finish working before starting to cool it down to lagering temperature so that it doesn't matter if  you stun the yeast dropping the temps.

I like Czech lagers so I'm not closing my mind to long lagering times, but personally I was happy with the results, as compared to other lagers I've done (and I've done several recently) and hope to enter some brews using this technique into the September comp to get a more objective assessment. (I did plan to enter this but it disappeared rather faster than I expected...) I feel that other variables like maximising the amount yeast I pitched, aeration, temperature control and lagering at -1C are more important. The Mexican Lager yeast is also really clean and I'll be using it again.
Title: Re: Lagering Questions
Post by: Donny on June 04, 2017, 12:34:47 PM
Quote from: DEMPSEY on June 03, 2017, 10:37:55 PM
By dropping it slowly you allow the yeast to continue its job where as a quick crash can stop the yeast in its tracks.
Gravity was 1.012 after 2 weeks so im thinking the primary was well over. Had pushed it up to 19C for a d-rest and it didnt drop any more gravity points. What Im getting at is that if youre 99% sure that its finished fermenting could you just drop to the lager temps?
Title: Lagering Questions
Post by: mr hoppy on June 04, 2017, 01:20:48 PM
That's the fast ferment theory. If the yeast is already in a stationary phase and the acetaldehyde and diacetyl are cleaned up it seems heat shock and other negative side effects usually associated with rapid temperature changes aren't an issue.

Not sure when you started raising temp. 50% of the way to FG seems to be recommended. I'm no expert but it seems from what I've read that if you leave the d-rest too late it won't be as effective.

In terms of knowing when to cold crash, if you check gravity again after 2 days you can know for sure if it is done.

It's also worth saying these techniques are also applicable to ales and I want to try them out on big hoppy beers to see if they can help cut aging and improve hop freshness.


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Title: Re: Lagering Questions
Post by: DEMPSEY on June 04, 2017, 03:21:14 PM
As I understand yeast they produce alot of crap in the frenetic early fermentation and that in the conditioning stage they turn on this crap to clean up the beer. Here is an old video clip talking about conditioning. https://www.youtube.com/watch?v=waOEv6mN3Bw
Title: Re: Lagering Questions
Post by: Gerryjo on June 04, 2017, 03:48:27 PM
Thanks for the recipe and certainly some interesting information to be read when I'm off nights.
@Donny sorry for the thread hijack though shall pursue with interest.

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Title: Re: Lagering Questions
Post by: delzep on June 04, 2017, 05:48:25 PM
Fast chilling can suck the liquid from the airlock into your beer meaning there is no barrier to keep the bugs out
Title: Re: Lagering Questions
Post by: mr hoppy on June 04, 2017, 09:17:02 PM
Quote from: DEMPSEY on June 04, 2017, 03:21:14 PM
As I understand yeast they produce alot of crap in the frenetic early fermentation and that in the conditioning stage they turn on this crap to clean up the beer.

Yup. The idea is to accelerate conditioning. I wasn't at brewcon but I thought this was what John palmers talk was about?

@ledzep

On air locks - 100%. But if you keep an eye and top up you should be ok. My airlock content froze😳
Title: Re: Lagering Questions
Post by: imark on June 04, 2017, 10:09:32 PM
Even if you don't drain the bubbler you'll pull air in when you chill the beer.
If you are fermenting in a carboy or bucket your options are limited. You could stick a large bag on the bubbler when you're near end of fermentation I suppose.
Title: Re: Lagering Questions
Post by: mr hoppy on June 04, 2017, 10:29:25 PM
Presumably that applies whether you go fast or slow?

Next job is to figure out how to work that spunding valve.
Title: Re: Lagering Questions
Post by: imark on June 04, 2017, 11:59:50 PM
That's true
Title: Re: Lagering Questions
Post by: Donny on June 05, 2017, 11:27:30 AM
If you go with the slow reduction it won't suck in the airlock contents?
Title: Re: Lagering Questions
Post by: imark on June 05, 2017, 11:34:54 AM
It'll contract as temperature decreases either way. Sucking in airlock content is probably more an issue of incorrectly filling it. The point really relates to pulling in air and specifically exposing it to oxygen at that stage. If you are concerned about that then you'd need to come up with a creative approach to avoid oxygen exposure at that point.
Title: Re: Lagering Questions
Post by: molc on June 05, 2017, 01:04:21 PM
Near the end of fermentation, empty the airlock and put a balloon on it. That will catch co2 and then as you cool your just sucking it back in.

Personally, I just have a low fill level and cool away with vodka in the airlock. If it gets in, no big deal.