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Mystery Fusels in Lagers

I’ve had issues with my last several lagers and I am pretty perplexed. I don’t do a lot of lagers but have done probably around 20 over my 11 years of brewing. My past five or so batches have had varying degrees of off flavors. I’m usually good at diagnosing problems but anything I’ve changed hasn’t seemed to remedy the problem. I believed the off flavor was a fusel and a friend with a great palate said the same without me telling him my opinion first. I’ll lay out the different things I’ve done and see if anyone else can pinpoint where it could’ve gone wrong:

  1. Most times I split batches and do two different yeasts. Sometimes I’ll do a kolsch in one and a lager in another. The kolsch doesn’t have the off flavor but the lager will.
  2. Different styles and recipes: maibock, Baltic porter, helles, o-fest, Schwarz.
  3. Three different yeasts, Bavarian, Munich and Augustiner. Some repitches off of previous batches, some new pitches grown to full sized starters.
  4. Hit with pure oxygen at pitching.
  5. Pitching at fermentation temperature.
  6. In one case, beer was done in four days so did diacetyl rise and got the flavor. Next time, I let it sit for two weeks before checking gravity and letting it rise. Same fusel flavor.
  7. Fermented in both glass and plastic at a consistent temperature, though varied over different batches from 46-54F.
    8 One of the batches I did a protein rest, most of the others were single infusion with no mash out. Same fusel flavor.
  8. No problems with ales made in the same system, same filtered campdenized water.
  9. Almost all Weyerman malts. Same flavor over the course of two different bags of pils.

Like I said, I feel like I’ve addressed everything that could cause it and have no idea what could be done differently. The only two suggestions I’ve had (and I plan on trying them) are to pitch at knock out temp and then drop down to fermentation temp and after two days at temperature, let it free rise to about mid-50’s. Any other suggestions? Thanks guys!

Have you checked your mash pH? How do you mill your grains? Could it be oxidation? All three of those can cause off flavors that can be perceived as fusels.

How do achieve chilling wort to fermentation temp? You racking off trub and cold break prior to pitching?

Not DMS, is it? Probably not, but it was the first thing that popped to mind - all that Pils malt. A short boil or a long time to chill can cause DMS issues if that’s it.

How long are you lagering for, and at what temperature? My lagers often seem to taste “off” until they age properly.

Have you checked your thermometer to make sure when you think you are fermenting at 50F, you really are at 50F?

Good suggestions everybody! I appreciate all the suggestions.

I am not checking my mash pH but I am getting similar flavors over all different color scales. I have a pH meter but hate maintaining it so I only really use it if I’m doing a really pale beer. I guess I should monitor it next time.

As far as oxidation goes, I purge all transfer vessels with C02 so I don’t think it could be that. I guess it could be a possibility but I’m usually really careful about oxidation.

On the grain crush front, I’ve got a homemade hopper with a crankenstein on it. I get a really good crush on the medium setting (love the three rollers) and when I upgraded, my efficiency jumped from 75% to 90%. At first I thought it was going to be too fine of a crush but I’ve had no problems with stuck mashes or tannic extractions. And I have no issues with off flavors on ales.

It’s definitely not DMS as I’m pretty sensitive to that one. I usually do a 60-90 minute boil for anything with a pils base.

As for lagering time, I do the Noonan rule of 1 week/2 deg P. The off flavor does appear to improve over the lagering time but doesn’t really seem to completely go away. My Oktoberfest finally lost all traces of it after lagering for five months. It had the lowest of the off flavor from the start though.

And the final question: how do I achieve fermentation temp? Depending on the time of year, I either chill with city water or city water with a finishing coolant of pre-chiller ice bath city water. Then I usually take it the rest of the way down to ferm temp by putting it in my chest freezer with the temperature set low and then raise to to ferm temp after a few hours. I don’t rack off the trub before pitching. For thermometers, I have the controller, a digital probe therm that I leave sitting on top of my bucket to double check and a laser gun infrared. All are within a couple degrees of each other.

Your processes seems sound. Nothing blatantly wrong.

Download and learn bru’n water. I don’t bother with my meter anymore. I suppose there could be some fusels being thrown as you are stressing the yeast if you are out of range in terms of pH. Ales yeast are probably more tolerant than lager. Can’t cite anything on that though. Maybe the ofest was better since it was darker and pH made into the zone?

You chilling your starter to ferment temps? I assume you are measuring wort temp prior to pitching. It takes me about 24 hours to get wort chilled from tap water 70F to 45F for pitching. I was blown away one time I measured for giggles. For years, I assumed it made it down just overnight. I was wrong.

I would try racking off trub. I only do this on my lagers.

That is an awful high efficiency which indicates that you could be over milling your grains. Over milling can cause astringent off flavors that can be perceived as fusels. You might not be able to tell in ales due to them being more complex or fruity due to the yeast and recipe.
Other than that I agree with Zwiller, your process is pretty sound. Maybe you are over pitching and making the yeast lazy and thus causing them to produce fusels.

Are the flavors sticking around long term, or disipating over time? The last lager I made seemed to have a bit of a fusel edge to it on first pour. After another week of cold storage it cleaned up very nicely.

[quote=“Loopie Beer”]That is an awful high efficiency which indicates that you could be over milling your grains. Over milling can cause astringent off flavors that can be perceived as fusels. You might not be able to tell in ales due to them being more complex or fruity due to the yeast and recipe.
Other than that I agree with Zwiller, your process is pretty sound. Maybe you are over pitching and making the yeast lazy and thus causing them to produce fusels.[/quote]
But that wouldn’t hold water if he used the same wort (split…), one with Kolsch yeast and one with lager yeast. The issue wouldn’t be part of the milling, mashing, pH, etc. because of that point alone… same wort split and pitched with 2 different yeasts. The only thing this suggests is that you’re pitching into wort that you think is fermentation temp but it’s too warm and you’re fermenting part of the batch at a higher temp which I suppose could cause fusel production. To be honest, after reading all of your points in your OP and I saw that you used the same wort split in two and one was good and one was not, it took a lot of variables out of the picture.

Also… and this already sounds like it doesn’t apply but still… many moons ago I used to save a lot of yeast. I would put lager slurries into the fridge that was set to 50° which is not a good place to store saved lager yeast because it will remain active. When I reused that yeast, I got some nasty flavors that I would describe as “wine-like” but not really. I eventually realized that it was the way I stored my lager yeast (this never happened with ales) and I went from saving yeast to directly reusing yeast by brewing on the same day that the previous beer was coming out of primary and using it THAT DAY. Also… How much yeast are you pitching? Are you comparing it to any of the online resources… YeastCalc, MrMalty, etc? I’ll be honest… I pitch lager yeast into wort that is around 50° but I’m sure I’ve pitched into cooler and warmer wort and I’m sure that I have under- or over-pitched by 200-300ml in the past and I have not had an issue like this with lagers in a very long time… and I brew a lot of lagers.

Loopy and Ken might be on to something. If you are way off on your pitch amounts, or if your yeast isn’t in the best possible health, that could be the source of your problem. You are aware that lagers require about double the cell count of equal gravity ales?

Or is it that you are using S-23 for all your lagers? That could do it…

Thanks guys! I appreciate the brainstorming session.

I’m definitely storing the yeast right (on water at 35F) but there may be one time that I over-pitched. Other times I’ve made up a full sized starter with the Mr. Malty calcs. After the off-flavor for the over-pitched batch, I did a yeast dilution to determine the concentration and built up a starter from that.

I’ve had a water analysis and adjust accordingly based on RA. For the most part, my water is perfect for SRM beers of 4-10 so I am in that range already with the lagers I’ve done. If anything, my water is a bit low in sulfate resulting in a maltier profile. Not a bad thing for lagers.

You’ve given me some ideas to chew on though. I’m going to coarsen my grain crush and see if that works. I’m also going to rack of the trub before pitching and make sure that the very center of my wort is at temperature. However, I feel that worst case scenario, the center of the wort may be 60-65F and the outside could be 50F. I don’t think that’s high enough to kick in fusel production.

Some good trivia:

Could you elaborate what lager yeast strains you are using? Wyeast/WL, etc. Not sure what the Augustiner is? WL 2352PC?

I assume this fusel issue is actually minor. IE you you not getting splitting headaches the next day and it’s not bad enough to consider dumping. Just trying to keep some perspective…

Interesting abstract you linked to. Good information to tuck away for later.

The yeasts used were WY2308 and WY2206. The Augustiner culture is from the Augustiner brewery in Munich and there is no equivalent WLP or WY of it. It’s only available through BSI but I got some slurry from a friend at a brewery that I stepped up to pitchable quantities.

The off-flavors do dissipate somewhat with age but rarely disappear completely. I’m going to brew another lager this weekend and really (really) check absolutely everything I can, record all values and steps, include the advice from above and see at what point it turns.

[quote=“beeristhemindkiller”]Interesting abstract you linked to. Good information to tuck away for later.

The yeasts used were WY2308 and WY2206. The Augustiner culture is from the Augustiner brewery in Munich and there is no equivalent WLP or WY of it. It’s only available through BSI but I got some slurry from a friend at a brewery that I stepped up to pitchable quantities.

The off-flavors do dissipate somewhat with age but rarely disappear completely. I’m going to brew another lager this weekend and really (really) check absolutely everything I can, record all values and steps, include the advice from above and see at what point it turns.[/quote]
I got a sample of that same yeast from a brewer in CO. Really nice yeast and I used it in a couple of different styles. I should have really tried to make something similar to Augustiner Dunkel because that is a great beer. I went to Europe last June and sampled that beer in one of the great Augustiner Bierhalls but at that point I had already brewed with the yeast and retired it.

My use of the Augustiner yeast was an attempt to curb some of the off flavors that I’ve had. There unfortunately isn’t a lot of information out there on it.

Ken, did you find that it attenuated more than expected? In the case of my last batch (the first with Augustiner) it finished at 1.009 while my the Munich (2308) finished at 1.011. This was despite a mash temp of 153F and 6% caramunich. Just curious if you had any info to share on your experience with Aug.

[quote=“beeristhemindkiller”]My use of the Augustiner yeast was an attempt to curb some of the off flavors that I’ve had. There unfortunately isn’t a lot of information out there on it.

Ken, did you find that it attenuated more than expected? In the case of my last batch (the first with Augustiner) it finished at 1.009 while my the Munich (2308) finished at 1.011. This was despite a mash temp of 153F and 6% caramunich. Just curious if you had any info to share on your experience with Aug.[/quote]
I had information from HERE
http://www.brewingscience.com/PDF/prodlist/BSI_Yeast_Descriptions_Guide.pdf
. I made some sort of Festbier and also a Pils, I think. The beers came out nicely and I only used the numbers from that page to determine if my standard lager primary temps would be okay with this strain. Very nice strain of lager yeast.

Thanks Ken. I did see that link on BSI but there’s not a lot of practical/anecdotal info out there. Looks like that’ll have to be my job!

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