Lager ferm temp & diacetyl rest

[Jag75]

@beerisyummy have you tried the canned wort starter yet?

 

[beerisyummy]

@beerisyummy have you tried the canned wort starter yet?

I haven't, do you recommend it?

 

[beerisyummy]

OK wait a minute. I just re-re-read John Oliver:

"Most lagers really develop their clean, finished character through an extended conditioning period of several weeks at temperatures on the low end of the yeast strain’s performance range.

So he's talking about "conditioning" here as distinct from "lagering" ??

 

[Jag75]

I haven't, do you recommend it?

Yes I highly recommend. It makes doing a starter a breeze. I also did a shakin not stirred starter with my Mexican Lager .

 

[couchsending]

There’s a lot of ways to skin this cat, it all depends on what you’re trying to achieve, what style you’re brewing, and what yeast strain you’re using.

Some people will advocate you pitch at 41 and ferment at 44 until completion.

Some will say pitch at 44, max out at 48, then slowly step down for the last say 30% of fermentation.

Others will say pitch at 50 and hold until completion.

Others will ramp up to room temp after 50% attenuation and think it makes no difference.

Up to you to decide what’s best.

Tips of advice.

Pitch more yeast than you think (2m/ml/* plato)
Aerate it really well
Pitch colder than you plan to ferment

 

[Jag75]

Definitely larger starters for lagers ^^^^^

 

[Bassman2003]

So if I ferment a lager at say 60, 62, 64 degrees, and I don't want to open the fermenter to check for diacetyl, do I need to do a diacetyl rest? This is the question I was hoping would get answered. I got kinda lost in the discussion a while back.

I would say no if you pitch a healthy amount of yeast. Try it out and see. If you notice an issue then do a rest next time, but 60f is not exactly very low for a lager. So the odds are in your favor.

 

[Bassman2003]

And in this article John Oliver does recommend a diacetyl rest - of 50 - 55° !!!
He also recommends a two-stage approach: "Most lagers really develop their clean, finished character through an extended conditioning period of several weeks at temperatures on the low end of the yeast strain’s performance range. Racking into a secondary fermenter allows this process to take place without creating any off-flavors or aromas." (I'm pretty sure this is where I got that idea.)

https://byo.com/article/10-keys-to-great-lager/

Wow, we are really all over the map on this, aren't we?

This is why I mentioned traditional vs "modern" lager brewing. Traditionally, 55 deg IS high for lager yeast. Things just take longer which can be counteracted with a large amount of yeast. Diacetyl reduction is nothing more than yeast activity. Higher temps or large amounts of yeast will eat the problem away. I remember Dan Gordon describing his lager procedure on a Brewing Network podcast and the crew was surprised at his 53f diacetyl rest which was a maybe from his point of view. He said if you do things right you do not need a D-rest.

One reason warm fermented lagers are popular and working well with homebrewers is that they are easier to 'do everything right' compared to a cold fermented lager which is a lot more involved.

 

[beerisyummy]

Diacetyl reduction is nothing more than yeast activity. Higher temps or large amounts of yeast will eat the problem away.

Bassman2003 ftw.

 

[Bassman2003]

We all win when information is exchanged.

 

[beerisyummy]

We all win when information is exchanged.

Heartily agree. However, there is altogether TOO MUCH information ... so I always appreciate veritas, succinctly stated.

 

[beerisyummy]

So to continue flogging the poor, dead horse.

Palmer (How to Brew, 4th ed. 2017) says diacetyl rest 4-7 days and then lager at 35° for a couple weeks. He mentions maturation but does not assign a specific part of the process to it. He further says, "The yeast should have cleaned up all the byproducts during the diacetyl rest, so all that is left to do is allow the yeast and haze to settle, which is purely physical, not biological."

Oliver, in the BYO article cited above, https://byo.com/article/10-keys-to-great-lager/ says "Most lagers really develop their clean, finished character through an extended conditioning period of several weeks at temperatures on the low end of the yeast strain’s performance range. (emphasis mine). Racking into a secondary fermenter allows this process to take place without creating any off-flavors or aromas ... many brewers incorporate a diacetyl rest after the bulk of the primary fermentation is complete ... The fermenter is slowly warmed to 50° to 55° F for two to five days. Then the temperature is dropped down to conditioning temperatures." And, he does not mention lagering per se.

It seems to me that "conditioning" ≠ "lagering." They appear to be two different things. It may be simply a problem of terminology, but I wonder if doing thing one way or t'other might be skipping over some beneficial processes. Like Bassman says,

... are aging and maturation the same thing? Is yeast always a part of the aging and/or maturation process or is it only really involved in maturation. What are we really doing when we age a beer?

I'm interested in what y'all think about "conditioning" and "lagering" (if not also "aging" and "maturation"). It does seem to me that fermentation + ramp-up + diacetyl rest + ramp-down + conditioning + cold crash + lagering is a bit much! The essential question might be, when do the yeast actually "clean up?" (Or, more elegantly put by White & Zainashek, "carry on reduction of fermentation byproducts.") Is it during the diacetyl rest as Palmer suggests? Or do we need a "conditioning period" at the lower end of the yeast's preferred temp range, as Oliver suggests? Or both?

I am holding at 46° (conditioning lol) until I make a decision. I really want to try to understand this, but right now the only thing I understand is why some brewers are like, "fuggit Imma warm-brew my lagers!"

I know, I know. I should RDWHAHB....

 

[Jag75]

I lager in my keg which is kept at 36-38 degrees . I have an Oktoberfest that's been lagering since April 2nd. My goal is to Lager till Sept 21st. My Mexican Lager is only gonna lager for 2 weeks until I tap it. Imo I'm conditioning and lagering at the same time because I'm in a sense cold crashing in a keg while lagering. I think of conditioning as cleaning up like getting the suspended yeast to fall clearing the beer . Lagering is more like storing , but it conditions at the same time .

 

[beerisyummy]

I lager in my keg which is kept at 36-38 degrees . I have an Oktoberfest that's been lagering since April 2nd. My goal is to Lager till Sept 21st. My Mexican Lager is only gonna lager for 2 weeks until I tap it. Imo I'm conditioning and lagering at the same time because I'm in a sense cold crashing in a keg while lagering. I think of conditioning as cleaning up like getting the suspended yeast to fall clearing the beer . Lagering is more like storing , but it conditions at the same time .

Fair enough. But what I'm noticing in the different sources is the reference to conditioning on the one hand, defined by Oliver as a rest at the low end of the yeast strain’s performance range, and lagering on the other, defined by almost everyone as taking place at thirty-something °F. In the former, my assumption would be that the yeast are still active, although at a very low rate; in the latter, the low temp would force the yeast into dormancy.

 

[beerisyummy]

So let's look at it this way. There are two processes that are at issue. (1) Yeast "clean-up" and (2) clearing the beer. I'm beginning to feel that "cleaning up" is dependent on yeast activity and "clearing" is dependent on time and gravity, therefore "conditioning" (as defined by Oliver) may be more important to the final outcome. So do we need that super-cold storage period at all? Someone argue with me please.

 

[McKnuckle]

I have fermented a few lagers in the serving keg recently (no transfers), using a floating dip tube. During this time, the entire colony of yeast remains in the keg, and the beer is drawn from the top, i.e. the clearest part. So my opinion is based on that practice.

I don't buy into a super-cold storage period. I ferment at 50. About 5 days after pitching, I begin rising slowly to 60 over some days, and hold for 48 hours once it reaches there. That's a brief period of warm conditioning.

After this warm conditioning, at which point the beer has fermented to FG and "cleaned up" (if needed; I don't check), I drop it 5 degrees per day until it hits 45F. Then I transfer it to a keg and place that in my serving keezer at 40F.

40F is where I leave it for the life of the keg. That's the lowest temperature it endures. Over the course of weeks, it cold conditions, which to me is certainly equivalent to lagering, and it carbonates. After 3 weeks at this temperature, flavor and clarity are markedly improved. This improvement continues and levels out somewhere around 6-8 weeks, at which point it's stable until the keg is finished.

From what I've read about lager yeast, I believe that it does indeed continue to metabolize something that contributes to "cleanness" in the flavor and appearance. This is in addition to just physically clearing, but it is admittedly subtle.

 

[Bassman2003]

Yes, this is really the heart of the matter. How much to do you gain over time in cold storage? The short and shoddy beers are proving that very acceptable beers are being made in non-traditional short periods of time. That is why I quoted the Beersmith podcast with Charlie Bamforth. It was his assertion and bet with a colleague that if everything was done well including "conditioning" as stated above, 1 week of lagering would be enough and taste as good as a long lagering period. This might be more for ales than hard core German lagers, I am not sure what his bet was. But, it makes you want to test it out. I do not have a 32.1 degree lagering chamber so I am not a good source of primary information. And there is a quite a bit of "good enough" in the homebrew space as it is our hobby, not business.

 

[Nate R]

Isn't the "joy" of this art (hobby) the various ways to do things? In other words... some people put nuts in their cookies some don't. And they will argue why their method is best. Likewise pizza MUST be deep-dish (or thin crust or whatever).
I think there are a few basic guidlines we must follow (sanitize, etc.). Other than that we are free to experiment and brew/ferment what we love.

Now that i've said that hippy-dippy sh*t... it takes me about 4-6 hours to brew. A batch takes at least 5 days to ferment. Add to that i don't have all the free time i would like to brew.... i would really really like this pilsner to turn out drinkable after these 2-8 weeks it is getting ready!

So i appreciate that this thread has been informative, polite, fact-based (i saw peeps dropping footnotes yo!), and encouraging in open discussion. Has given me lots of info to make my choices for my beer.

Now let me tell you why if you add nuts to your cookies you are a stupid moron....

Cheers/Prost/Salute all!!

 

[Jag75]

Nice post and I love the end ^^^^^

 

[beerisyummy]

Nate R: Noice.

 

[mediant]

I'm interested in what y'all think about "conditioning" and "lagering" (if not also "aging" and "maturation"). It does seem to me that fermentation + ramp-up + diacetyl rest + ramp-down + conditioning + cold crash + lagering is a bit much! The essential question might be, when do the yeast actually "clean up?" (Or, more elegantly put by White & Zainashek, "carry on reduction of fermentation byproducts.") Is it during the diacetyl rest as Palmer suggests?

Fermentation byproducts include VDK-precursors, acetaldehyde, sulfur compounds. For various reasons, their reduction is completed more efficiently at warmer temperatures, hence warmer D-rest is usually recommended.

Or do we need a "conditioning period" at the lower end of the yeast's preferred temp range, as Oliver suggests? Or both?

Quoting:
During maturation, the residual yeast will excrete compounds (i.e., amino acids, phosphates, peptides, nucleic acids, A) into the beer. The amount and quality of these excreted materials depend on the yeast concentration, yeast strain, its metabolic state, and the temperature (N.N. 2000). Rapid excretion of material is best achieved at a temperature of 5–7C over 10 days (Van de Meersche and others 1977). When the conditioning period is too long or when the temperature is too high, yeast cell autolysis will occur. Some enzymes are liberated (e.g., a-glucosidase), which will produce glucose from traces of residual maltose (N.N. 2000). [...] The increase in amino acid concentration in the beer has a positive effect on the flavor fullness of the beer. Undesirable medium-chain fatty acids can also be produced in significant amounts if the maturation temperature is too high (Masschelein 1981).

This essentially says that cold maturation is beneficial for flavor development, yet care must be taken to avoid autolysis, which is even more important for ale yeast. Autolysis releases a-glucosidase, which is similar to glucoamylase that diastaticus strains release extracellularly, as well as esterases that break down those flavor compounds, so it is beneficial to separate the beer from the yeast cake, especially for a long maturation or when not properly cooled.

 

[cactusgarrett]

Similar to what slowly reaching the conditioning/lagering temp might do:

How To Brew”, 4th edition, page 95:

”Cold conditioning is a process of slowly cooling the beer down by 2F(1C) per day to about 9-15F(5-8) below the fermentation temperature to promote the flocculation of the yeast and the coalescence of the protein-polyphenol complexes that cause haze...
The point of slow cooling is to prevent thermal shock of the yeast cells and subsequent excretion of fatty acids and other lipids. These lipids can interfere with head retention and will readily oxidize, creating stale flavors. Thermal shock at any time can cause the yeast cells to release protein signals that cause other yeast cells to shut down to protect against the cold, potentially leading to premature flocculation and under-attenuation.”