Lagering

[PostModern]

Well, if you did, you could have a method named after you. :lol:

The "deadly" No Lager Method... yeah, I can see that catching on

 

[///]

The "deadly" No Lager Method... yeah, I can see that catching on

Or no Larger Method.

Since the economists came to town, who dared lager at more than -1 c for 4 days then filter the crap (it is lager after all) ? Not many majors would do any different it would seem!

 

[Weizguy]

I just checked my copy of Brewing Science and Practice (2004), and there is significant info re maturation/lagering, including a bit about yeast metabolites and temperature. In fact, and entire chapter, Chapter 15

I found the book as a free download on the web. It's about 850 pages in size.

An excerpt states:

Beer changes or treatments after primary fermentation but before
packaging therefore comprise:
maturation; flavour and aroma changes
stabilization against non-biological haze
carbonation
biological stabilization (pasteurization or sterile filtration, Chapter 21)
clarification and filtration.

and another:

Several important groups of compounds have been identified as changing during the
maturation of beer with consequent positive effect on beer flavour. The most important
are: diketones (especially diacetyl), sulphur compounds, aldehydes, and volatile fatty
acids.

Try to find the book and you'll see that there is a yeast effect on flavour profile during extended lagering.

Seth

 

[sstacey]

This is an interesting post because I have just been reading through university brewing textbooks (also used as commercial brewing textbooks) to find out what chemical changes take place in the beer during lagering. All the textbooks are very brief on the subject. More importantly, a number of mass produced lagers are run through a filter-like system that contains yeast, the idea being that the yeast rapidly cleans the beer of diacetyl precursers, negating the need for a long lagering process.

If I do a diacetyl rest and the sulphur has also gone then I tend to agree that the majority of work has been done and the beer should be pretty drinkable.

I have not found any authoritive text that really explains the biochemical changes during lagering, but I think these are the main issues.

 

[sstacey]

I filtered my no lager lager yesterday, kegged it and it tastes fantastic.
To be fair it's a dark lager so it could hide off flavours.
Fermented at 12C, diacetyl rest at 17C, chilled for 1 week while I fined the beer.
Filtered, kegged, tastes really smooth. :beer:

I don't know how a pils would go but from now on I won't be lagering my dark lagers for any length of time.
This means it can be an everyday beer because I don't have to tie up fermenters and fridge space.

 

[Stuster]

Wow! That's fantastic! Sounds like a huge difference in time, effort and fridge space. :super:

What yeast was that with?

 

[sstacey]

Saflager 34/70

It will be interesting to know how a light lager goes.
I am really happy with how clean this beer tastes. I did let it attenuate very well. I think this is important for brewing lagers, particularly to clean up diacetyl.

 

[Darren]

I suspect all that "lagering" does is allow the brewer to make a clearer beer.

Thats it!

 

[Stuster]

That was my suspicion, Darren.

Les, those are important changes that happen during maturation, but how are those changes affected by temperature? The time lagering is maturation time, though that could be done quicker at higher temperatures I'd have thought, since 10C or so is the yeast's optimum temperature for activity. :unsure:

 

[DJR]

Next lager i do (a Boh Pils) is going to get the following process to test out the "no/reduced lager time" theory

Ferment at 8-10C with a large starter for 7 days or until gravity reaches 1020 (target FG 1015)
Get out of the fridge to allow a d-rest at ambient temp (about 18C atm) for 4 days
Rack after the 4 days (add a bit of sugar for headspace protection) to a secondary and leave for 1 to 2 weeks at ambient temp
Lager in the fridge for a week or two after that

Total process time about 3.5 to 4 weeks

Hopefully the end result should be as good as the last lager i did which was lagered just after the d-rest for 3 months, but i'll be able to tell once it's lagering whether it needs longer still. If i save even 1 month of the lagering time then it's worth it.

 

[neonmeate]

this is interesting stuff.
i am no biochemist and i haven't brewed a lager for the last year since stuster came and took my brewfridge, but i have REALLY noticed the difference between beers i have lagered longer vs beers that have had brief lagerings but matured in bottle at room temp. this has been most pronounced with some of the czech yeasts like WLP800 and 802 that had big diacetyl and sulfur contents. the 34/70 didnt seem to need lagering at all but i find this yeast produces pretty safe, shallow beers.

i certainly notice the difference between australian microbrew pilseners that are full of esters, DMS, diacetyl and hop resins, vs traditionally brewed czech/german pilseners (i'm talking the good ones) that are lagered for 3 months+. they're chalk and cheese. i always assumed it was the lagering time, perhaps it is just the initial fermentation that is carefully looked after.

 

[DJR]

I've looked into some of the Czech brewing practices and i found some interesting things

- german brewers use a yeast that doesn't flocculate well until about 0C, so lagering at around 0C still means you have active yeast
- Czech brewers use yeast that flocculates below about 3 or 4C, lagering at around 0C has inactive yeast because it's flocculated (crashing yeast) which leads to the residual sweetness in Czech lagers
- The Czechs seem to control diacetyl by krausening with fresh wort just before lagering - but judging by Budvar/PU's palate, they want a bit of residual diacetyl

Now if the yeast has flocculated at 0C and then lagered for 3 months, there is going to be no/very little diacetyl takeup, which is why they get the buttery flavour, but the cleanup process - getting rid of sulphur etc - is going to be very slow with flocculated yeast, as well as the takeup of sugars, some of which are left over after the end of a Czech lager fermentation/maturation.

All it does is lead me to believe that if the yeast have an effect on the "cleanliness" of the beer then we might as well leave them in suspension at ferment/d-rest temp till they're done and the beer tastes non-sulfury and fairly clean, then crash cool it to get the yeast and tannins/polyphenols before bottling.

 

[facter]

I just checked my copy of Brewing Science and Practice (2004), and there is significant info re maturation/lagering, including a bit about yeast metabolites and temperature. In fact, and entire chapter, Chapter 15

I found the book as a free download on the web. It's about 850 pages in size.

An excerpt states:

Beer changes or treatments after primary fermentation but before
packaging therefore comprise:
maturation; flavour and aroma changes
stabilization against non-biological haze
carbonation
biological stabilization (pasteurization or sterile filtration, Chapter 21)
clarification and filtration.

and another:

Several important groups of compounds have been identified as changing during the
maturation of beer with consequent positive effect on beer flavour. The most important
are: diketones (especially diacetyl), sulphur compounds, aldehydes, and volatile fatty
acids.

Try to find the book and you'll see that there is a yeast effect on flavour profile during extended lagering.

Seth

free download seth? Can you post it or a link to it?

 

[Stuster]

Here you go.

 

[facter]

thats awesome, thanks... another ebook for my collection ..im pushing over 100 different books and files now hehe

<3 ebooks

 

[hopmonkey]

I have a few thoughts, from a chemical side of things.
Yeasts produce hydrogen sulfide as a byproduct of fermentation, lager yeasts more than ale.
In a normal ferment the yeast will rework this h2s and reduce it somewhat but most of it is reduced by evolving co2.
In a cool lager ferment the yeast action is slower, than ale, so there isnt the massive amount of krausen and c02 evolved, therefore more h2s in solution.
So how to get it out?
The solubilty of h2s is lower at lower temps, so cool it down and hey presto it starts to come out of solution.

Perhaps our yeasts are much better these days at minimising initial h2s production than of 10-20 years ago, much like our malts are more highly modified, and this is why we are seeing cleaner non lagered beers? It maybe even asomething to do with the malts?
Perhaps soon we will have a 'lager' yeast that fast ferments at room temp and produces clean beer as fast an easy as an ale? Hope so!

 

[Stuster]

Well, according to Brewing Science and Practice that Les mentioned

Generally, undesirable concentrations of hydrogen sulphide are reduced during cold storage times of 5-7 days.

So for H2S, a week of lagering should be fine. But they also say it might depend on the presence of DMS. This can be reduced by a long, strong boil. How much is present will depend on the malts, with Australian malts having much lower concentrations of the precursors to DMS (SMM). So, it seems to me that you are right, that the malts we have will lead to less sulphide production. They also suggest that strong fermentations might purge hydrogen sulphide from the beer due to the vigorous production of CO2. (All that on pp.562-3).

The book mentions three other changes during maturation. Diketones (diacetyl and others), aldehydes (acetaldehyde and others), and volatile fatty acids. Diacetyl is removed by a rest at a higher temperature. Aldehydes are mainly to do with oxidation from poor transfer techniques. Volatile fatty acids they say that

Maturation is seldom controlled specifically from the viewpoint of controlling volatile fatty acids.

So, I can't see any reference in this to ways in which cold temperatures might be important to the maturation of the beer. What is mentioned is that the beer is often chilled to settle out the yeast, and to clear haze. This is very important to commercial breweries to give long shelf life in any conditions. They also say that for commercial breweries they can

At least one successful system comprises: fermenter filling 20 hours, primary fermentation 72 hours, warm storage 48 hours, cooling 48 hours, cold storage at 1 C (30 F) 36 to 48 hours. Total time is less than ten days.

I can't find any more information on lagering mentioned in the 863 pages.

Wow. I've had a PP moment. Time for a beer. :chug:

 

[matti]

Thanks Stuster and everyone for this thread.

I have not got a fancy filtering system and will continue to lager my lagers.

- The Czechs seem to control diacetyl by krausening with fresh wort just before lagering - but judging by Budvar/PU's palate, they want a bit of residual diacetyl

I tried this and got a very close profile to Chech pilsner but I prefer German lagers which are generally lagers for some time and the

I believe the aussie lagers are all crashed and filtered and when drank at very cold temps are fairly tasteless but easily drunk.

But the megas swill have caught on and efforts are made to improve palates.

 

[redbeard]

I was listening to a pope podcast recently (aka jamil) & he mentioned that he pitches yeast cold into a cold wort, then lets it warm up to ideal lager yeast temp (10'?) and then waits 3 or 4 weeks before kegging / bottling. He thinks this way avoids the diacetyl rest and allows a full ferment. I cant remember if he cc's after or just kegs it. I think it was on the show about bocks.

mm might have to try the no-lagering lager for empircal science reasons

 

[milpod]

The Germans are rarely wrong