Fermentation General Process Review

[kstiglich]

Thanks Bassman,
And just to confirm.... when German brewers perform their lagers at very low temp, they are not expecting any activity from yeast, and they are just expecting a natural clarification and maybe other chemicals events not involving yeast, or do they have any special yeast strain that even at that low temp will work slowly but not dormant???

 

[Bassman2003]

Brewing has changed a lot and even in Germany production is being altered for cost reasons. But, in the traditional method, crash cooling is not used. The beer is slowly lowered to lagering temps as to protect yeast heath. The remaining yeast in suspension will take part in naturally carbonating the beer, so they do not want to shock them by crash cooling. Sometime they will add yeast that will spark CO2 production as well, but that is after lagering in bottling or kegging.

Do the yeast do anything in the lagering phase? I do not know for sure. The majority of the yeast is left behind in the primary which lets them lager for long periods of time. Many say a month is the max you should let your beer sit on the primary yeast. So for homebrewers, some steps overlap with the yeast, and most of us do not naturally carbonate. So we can treat the beer in a little different manner as we do not need to protect any yeast health beyond the primary fermentation.

You might want to go listen to archived shows of The Brewcasters "Sunday Show" which is on the brewing network website. Look for the shows with Dan Gordon of Gordon Biersch brewery. He is a Weihenstephan trained brewer and goes into extensive explanation of their process in the brewery (which is run like a traditional German brewery). I think he has been on 4 or 5 times and really sheds a lot of light on brewing practice and even gives his recipes. His Dunklesweizen recipe is awesome.

 

[kstiglich]

I just heard Dan, and he confirmed to ferment on 48 to 50f max for lager...the most interesting I heard there is that yeast propagation should be done at fermentation temp, so next time I will do my first starter at 48f. I guess it will take longer, but I would like to see any beer improvement!

 

[passedpawn]

An interesting read for you:

http://byo.com/stories/issue/item/870-how-do-commercial-breweries-lager-so-quickly

 

[kstiglich]

An interesting read for you:

http://byo.com/stories/issue/item/870-how-do-commercial-breweries-lager-so-quickly

Thanks Passdawn,
I believe Mr. Wizard response is a Little confusing.

Initially he says that most brewers consider diacetyl reduction to be the key goal of lagering, but I believe that diacetyl reduction cannot be achieved at 32f. So noone should think that he refers to lagering at 60f or 70f, but lagering implies cold temperatura right? (I think some would confuse from this statement that you can lager in warm temp)

Later on the same doc, he mention that in recent years, large brewers have begun to warm the beer between fermentation and lagering to accelerate the consumption of byproducts.. (Now he is confirming that there is a fermentation stage, a “conditioning” stage at a warmer temperature and a following lager stage).

I would conclude that Mr.Wizard wants to say that after fermenting you can warm your beer to let all by products be consumed by yeast, and then lager for clarification close to 32º. and the confusion would appear, because actually, after your primary fermentation finish, you can stay at your fermentation temperature such as 48f and the byproducts consumption will occur, and you are cold, not 32 but cold, so probably you can start calling this stage your lagering stage.

From my point of view and in order to avoid misunderstandings, I prefer to refer to lager for temperatures between 40f and 32f, do you agree?

 

[passedpawn]

When you say lager, yes I assume you mean keeping it at cold temperatures. I lager at 30F. I make large batches of beer, so when I'm serving one keg the others are lagering at 30F.

I think Mr. Wizard is saying the same thing I have, that you have 3 distinct things you are trying to accomplish: ferment the beer to create the alcohol, allow the yeast to break down byproducts of fermentation so they don't leave any off flavors, and clear the beer.

So,

• Ferment at 50F for 3 weeks.
• Get the beer warm (65F) for a week, thus greatly increasing the metabolism of the yeast, and greatly decreasing the time to remove diacetyl, etc.
• Clear the beer by either letting it sit at cold temps (30F) for extended periods (months), or filter and drink as soon as it's carbonated. If you are lagering over months, I'd transfer to secondary first if you have a way to do that without introducing much O2 into the beer.

Thanks Passdawn,
I believe Mr. Wizard response is a Little confusing.

Initially he says that most brewers consider diacetyl reduction to be the key goal of lagering, but I believe that diacetyl reduction cannot be achieved at 32f. So noone should think that he refers to lagering at 60f or 70f, but lagering implies cold temperatura right? (I think some would confuse from this statement that you can lager in warm temp)

Later on the same doc, he mention that in recent years, large brewers have begun to warm the beer between fermentation and lagering to accelerate the consumption of byproducts.. (Now he is confirming that there is a fermentation stage, a “conditioning” stage at a warmer temperature and a following lager stage).

I would conclude that Mr.Wizard wants to say that after fermenting you can warm your beer to let all by products be consumed by yeast, and then lager for clarification close to 32º. and the confusion would appear, because actually, after your primary fermentation finish, you can stay at your fermentation temperature such as 48f and the byproducts consumption will occur, and you are cold, not 32 but cold, so probably you can start calling this stage your lagering stage.

From my point of view and in order to avoid misunderstandings, I prefer to refer to lager for temperatures between 40f and 32f, do you agree?

 

[kstiglich]

I totally agree with the whole process...
I think confusion appears when we start naming each part of its processes and where each process starts and finishes....

 

[Bassman2003]

My only thoughts from the above method is performing the D-rest after three weeks. I have heard Palmer speaking about this and how the yeast will be mostly dormant after three weeks. So even if you raise the temps, the yeast will not be very active. I got the impression that doing the D-rest earlier while the yeast are more active would be better. It is said the "beer" is formed within 5 days of active fermentation. So one does not need to wait three weeks to avoid off fermentation flavors.

D-rests are like decoctions - everybody seems to have a different opinion. In the Dan Gordon podcasts, he refers to not even doing a D-rest for their beers. Stating that if you do the rest of the process correctly you do not need to do a D-rest.

Dan also talks about starters as kstiglich mentioned. He propagates at fermentation temps because they pitch the entire starter at high activity. (They also use the same wort from the batch/style of beer they are brewing for the starter). Everything they do is numbers/measurement based. So they know when to move to the next step based on science and taking readings. Most homebrewers do not measure the free amino nitrogen amount based upon their malt... So it is safer for us to be a little more general with what we do.

I have decided to start pitching at high activity instead of chilling and decanting my starters to see if anything is different. I have made one beer like this and the lag time was shorter.

Glad you liked the podcast kstiglich. The program is kind of rowdy but the information from Dan is just golden. Amazing that he is willing to share so much.

 

[passedpawn]

I often don't have complete fermentation until 3 weeks. I.e., I usually take a gravity reading after 2 weeks, and many times (like the Ocfests I'm making now) the beer is still several points off the FG. In the case of the lagers I'm doing now, I have them at 62 for the last week to finish fermentation completely, including reduction of butter, green apple, sulfur, etc.

Assuming the beer is at final gravity, I'm going to crash mine today to 30, and tomorrow or Tuesday I'll filter and keg and carbonate.

I've been working on making good pilsners for a long time, and still haven't perfected them, so I don't mean to suggest I have the best method. It's just where I'm at now. Ask me in a couple of years and the story might be quite different!

My only thoughts from the above method is performing the D-rest after three weeks. I have heard Palmer speaking about this and how the yeast will be mostly dormant after three weeks. So even if you raise the temps, the yeast will not be very active. I got the impression that doing the D-rest earlier while the yeast are more active would be better. It is said the "beer" is formed within 5 days of active fermentation. So one does not need to wait three weeks to avoid off fermentation flavors.

D-rests are like decoctions - everybody seems to have a different opinion. In the Dan Gordon podcasts, he refers to not even doing a D-rest for their beers. Stating that if you do the rest of the process correctly you do not need to do a D-rest.

Dan also talks about starters as kstiglich mentioned. He propagates at fermentation temps because they pitch the entire starter at high activity. (They also use the same wort from the batch/style of beer they are brewing for the starter). Everything they do is numbers/measurement based. So they know when to move to the next step based on science and taking readings. Most homebrewers do not measure the free amino nitrogen amount based upon their malt... So it is safer for us to be a little more general with what we do.

I have decided to start pitching at high activity instead of chilling and decanting my starters to see if anything is different. I have made one beer like this and the lag time was shorter.

Glad you liked the podcast kstiglich. The program is kind of rowdy but the information from Dan is just golden. Amazing that he is willing to share so much.

 

[Bassman2003]

I am always a fan of finding what works best for your setup and tastes. What makes this complicated is that commercial brewers have very short primary times compared to homebrewers. When they refer to raising the temps after fermentation slows and that often means 6-8 days after pitching.

Kai has some great references about fermentation regimes on this page towards the bottom - http://braukaiser.com/wiki/index.php?title=Fermenting_Lagers

The tradition German method does not have a temperature increase. The beer spends a week or less on the yeast, transferred and is then slowly dropped to freezing where it will stay for 6 weeks or so. If you had a dedicated lager fridge, this would be the way to go, but many of us do not have three fridges just for our brewing. So Kai suggest schedule "F" for most homebrewers which has the temp increase to 60F then down to lager temps. But, if you look at the graph, the technical paper shows the increase up to 60F happening on day 8 of fermentation. Much earlier than us homebrewers would think to raise a lager fermentation.

I don't know what is best but it is food for thought or experiments.

 

[kstiglich]

In the case of home brewing, where many people would have mistakes in pitching rate, temperatures and other factors that would increase diacetyl and other off flavors, thus performing a diactecyl rest would be better, but the ideal way is to improve all the process and not needing a D-rest !! I just tried two lager batches and I did D-rest in both but never tried those beers before the D-rest, so I do not know if I needed or not. Now that I am fermenting two lager batches, I am not going to do D-rest, hope I do not needed.

I understand that commercial brewers would improve their process in terms of the most economical benefits with a good/acceptable flavor on their beers.
So maybe the commercial fermentation process is not the best process you would follow, even with all the technology and budget for it.
From this point of view, and considering that I have two dedicated freezers for my fermentations....what do you think is the BEST process for fermentation, considering the optimal fermentation from a flavor perspective, but time.
Do you think that optimal fermentation would be 3 weeks on 48f and then cold crashing to 32º for 2 days, then transfer to keg, filtering the beer, and force carbonation?
Do you think that considering and exclusive fermenter for every batch, is there any schema that would optimize on my fermentation?
I am considering filter my beer...I tried filtering before but with 5 microns and I had bad results....I did not had any change on beer before and after filtering it...I would try it again with 1 micron.

 

[Bassman2003]

I think optimum would be your example but to put the keg in a 32F environment for 6 weeks. Then move the keg to a serving fridge.

Imho, the only thing not to follow from a commercial brewery is their processes to save money. People like Dan Gordon have a bottom line to meet but, they are trained brewers and know more about the process of making beer than homebrewers. So for me, I like to be open in learning from them and adapting what I can to my experience.

I never cared about filtering my beer. It is more for sales & show than anything else and I do not sell my beer.

 

[passedpawn]

I never cared about filtering my beer. It is more for sales & show than anything else and I do not sell my beer.

The stuff that clouds your beer has a significant effect on the taste. I know you care about the taste. In the case of an IPA or most ales, that stuff is a benefit. In lagers, it's wrong wrong wrong.

Second, the look of a beer is important to beer drinkers. You drink first with your eyes. If you really don't care what your beer looks like, then more power to you, but most people do care.

 

[Bassman2003]

I never said my beer was not clear, just that I never wanted to filter it. When I was in Munich a few weeks ago I had some beers at the Ayinger restaurant. They had an "original style" lager on tap that was unfiltered. They were proud of it and it tasted great.

Leaving a beer in the primary for 3+ weeks at cold temps leaves the beer pretty clear upon transfer in my experience depending some upon the yeast that was used.

 

[kstiglich]

I think optimum would be your example but to put the keg in a 32F environment for 6 weeks. Then move the keg to a serving fridge.

Imho, the only thing not to follow from a commercial brewery is their processes to save money. People like Dan Gordon have a bottom line to meet but, they are trained brewers and know more about the process of making beer than homebrewers. So for me, I like to be open in learning from them and adapting what I can to my experience.

I never cared about filtering my beer. It is more for sales & show than anything else and I do not sell my beer.

Bassman,
The idea of putting the keg in 32f for 6 weeks is just for sedimentation/clarification, or is any other flavor /chemical process occurring on that phase???
I am asking because 6 weeks are 6 weeks!!! I will wait in the future, but now I want to know if I already have a good recipe! So I am desperate to taste my beer...
It would be great if I can produce a clear beer just clarifying it at 32f for a short period, otherwise I have used gelatin before with great results... It reduce your clarification time in 48 hours!
Finally, My objective is to sell my craft beer someday!

 

[Bassman2003]

In the tradition German brewery, there is still some fermentation going on which is why they slowly lower the temps to protect the yeast. But, they have a 7-8 day primary. So they need the next phase to finish the beer and catch some carbonation. In homebrewing, we finish the beer in the three+ week primary. So the lagering phase is not as (if any) yeast intensive. But, that does not mean it is not important.

Lagers can be a challenge due to the longer times they need. But, it depends upon your tastes. The first few lagers I did were sampled two weeks after I transferred them. They tasted really good, but as time went by I noticed they tasted better... So you learn to wait

As far as clarity goes, I have found it depends upon the yeast a lot. 34/70 will clear pretty well on its own. I used WLP Southern German Lager once and while the beer was excellent, it took a while in the keg for it to really clear up. 34/70 cleared in the fermenter.

A lot of variables.

 

[kstiglich]

Considering that we are cold crashing our beers, and keeping them at 32f for lagering we must asume that yeast are dormants and not affecting the beer at all. But it is also real that during lagering the beers change their flavor, so any chemical process would be taken during that phase besides clarifying the beer right? Otherwise, i would clarify by mechanical processes, but finally, there is also a chemical event during lagering that must be donde by keeping your beer at 32f or similar temp for a while....

In that case, I will check my peroni clone to see how much clear it is, and depending on it I would use or not gelatin. After that I will force carbonate my beer and try it during the lagering process to see how lagering affect flavor.

 

[Bassman2003]

Yes, you have to taste your first attempts to see how your process is working. Tasting early will still taste good and you might find out early is good enough.

 

[kstiglich]

It is just an update of my Peroni lager clone...
It is on its 18 day, and still on its primary fermenter. It is pretty clear, and its gravity is on 1.012.
Tasting it I could not find any Diacetyl or any off-flavors, so I am pretty happy with the current flavor. I will keep it at its primary fermenter to accomplish their 21 days (3 weeks) at 53f. This sunday I will cold crash for a couple of days, and then I will transfer to a keg. I believe I will not need to filter my beer!!
Do you think that there is any difference between 1) kegging, 2)carbonating and 3)lagering, versus 1)kegging, 2)lagering and 3)carbonating?

I would prefer first schema, because carbonating early will let me taste the beer on its progress due to lagering....

 

[sherwicf]

Fermentation on ALE with Dry hopping
1. PRIMARY FERMENTATION: 10 days in primary fermentation -> It would be done in the right temperature for the ALE strain yeast (Typically between 60 and 70º)
2. DRY HOPPING: 7 days in carboy at the same temperature used during primary fermentation.
3. Transfer to a Keg (Oxygen free with CO2 in head space but not carbonated)
4. MATURATING: Wort must be conditioning at warm temperature for 1 to 3 weeks @ 68º~70º to ensure that yeast clean everything in the wort.
5. COLD CRASH: Cold beer to 32º~34º
6. CLARIFY: Use gelatin to clarify your beer for 48 hours at least.
7. FORCE CARBONATION: Start force carbonation @12.5 or required PSI.

Not trying to hijack, I'm trying to get some information on this process specifically. I've read elsewhere that dry hopping should occur at lower temperatures?

 

[kstiglich]

Actually, you can dry hop whenever you want, you only need to be sure the beer has alcohol to avoid an infection, then you can only start it some days after your active fermentation.
Anyway, the exact moment to throw your hops, depends on the effect you want on your beer. Typically, most of the people dry hop after active fermentation, and considering that if you want to dry hop for X days, then you will start dry hopping X days before you transfer your beer, because it is a way to remove those hops and avoid some grassy flavor for long dry hopping.
Anyway, there are some people that dry hop even in carbonated keg...so you can try anything, but usually the suggested time here is the most common for the benefits/cons and warmer temps work best because aroma oils are not as soluble at low temperatures.

 

[Bassman2003]

I don't really know if it matters when you put the gas on. I have done both. It is good to leave the gas on for a little while right away just to ensure you keep some pressure in the keg as the CO2 is absorbed into the beer.