Crooked Stave's Diacetyl Problem

Lost Abbey set the precedent. Hyped up brewery with a reserve club starts churning out less than stellar beers for premium prices, some with serious flaws. We've seen this before.

 

Then there was Batch 60, which was a glimmer of hope, until the diacetyl problem hit it. (And yes, I'm drinking a bottle right now).

 

Red swingline is a better beer anyway, and I have NEVER gotten diacetyl from that beer...

 

Actually diacetyl is mostly from the start of fermentation, not the end, it should be getting better over time, not worse, unless there was too much diacetyl produced in the beginning and either not enough yeast or weak yeast that cannot clean it up anymore. But maybe that's what you meant was "best after date" since you were talking Deschutes.

Other issues that cause it aside from insufficient yeast is a lack of aeration, or pitching the yeast while the wort is still warm and lowering the fermentation temperature, or refrigerating too quickly and not doing a diacetyl rest (55-60'F) to allow the yeast to eat the diacetyl.

The only thing I could think of that would be the contract brewers fault would be aeration.

I'm also wondering about the yeast strength, I'm pretty sure Chad's on top of it, but I've always heard that around ~10 generations of yeast that you should start over with a fresh culture as the yeast tend to mutate (can produce off flavors, specifically diacetyl) -- This at least makes the most sense considering I store my beer in 55-60'F range and still had diacetyl in a 6-month old bottle of Persica, so presumably there was not enough yeast to clean it up in some bottles.

 

Pedio (and Lacto) metabolism is usually what is causing high levels of diacetyl in sours. As the beer ages, you need something like Brett to eat away at the diacetyl, and the Brett will actually do its best metabolic work around 75-80 degrees. It's part of the reason younger sours have a creamier texture and flavor. Adding fruit later in the process can start the cycle again and provide Pedio and Lacto more diacetyl production fuel.

Aeration should not be an issue as the barrels will allow some oxygen in. A diacetyl rest is more intended for lagers that are fermented at cool temperatures. I would hope the months and months in the barrels at around 60 degrees would be enough time at that temp. I don't know if sours really have much of an issue with mutations considering they are wild/semi-wild fermentations, but I guess its at least a slight possibility but pretty unlikely.

Chad seems like a smart guy and from his thesis site, I would be willing to bet he knows a lot more about this stuff than any of us. I'm willing to chalk it up as one of the many hard to control issues with making sour beers. For now, I always store my Crooked Stave bottles with that may have diacetyl issues at room temp for a couple months before cellaring and I've never had any issues. It also helps speed the process to gently agitate the bottle every couple weeks.

 

All good points and mentioned before, but I'm pretty sure that Batch 60 is 100% Brett, so that wouldn't explain the diacetyl in that. The pedio explanation only makes sense for Persica & Surette as both of those use bacteria I believe. Diacetyl rest is typically used in lagers, but still relevant here and essentially it's the exact same thing as what you and I said about raising the temperature to allow the yeast/Brett to become active again.

 

so much bottle variation.
opened my last Persica blend2 a couple of weeks ago and it had completely cleaned up (compared to fresh). still have 1 Batch60 left but havent had any diacetyl issues with those (the St Bretta seasons on the other hand... ugh)

 

Ha! Yeah, sounds about right. Just like they will have more tulips for sale the next time I am in

 

Batch 60 is barrel aged. Is it possible the diacetyl came from the bugs from the barrel?

 

My guess is you are right @lordofthelambics. I'm pretty sure Brett can produce AAL (a-acetolactate) an intermediate in valine production which when oxidized, turns to diacetyl. Sacchro can produce it, hence the possibility of diacetyl in non-sours, so I would assume that Brett can too. That said, I would guess that it is Pedio and Lacto in the barrels. That would also explain why it spans the entire range of beers.

@Prospero The diacetyl rest is not really relevant in non-lagers (with the exception of homebrews that may be crashed too early) because barrel aging (or pre-bottling bright tank resting in the case of non-sours) already occurs at the temperature that a rest would occur at and happens over a longer time period than would be necessary. I doubt they are barrel aging for less than a couple days. I mention raising the temp in reference to already bottled beer. A diacetyl rest would occur before it even hit barrels. I do it just give the Brett a competitive advantage over anything else that is in there and to speed up its metabolic process.

 

@cptnspeed1, yes I understand the traditional use of the term diacetyl rest but wasn't suggesting the typical time you'd do it as you would with lagers... I was merely implying that raising the temp in already bottled beer, is essentially the exact same thing as a diacetyl rest -- that is raising the temperature with the purpose of reactivating the yeast (or in this case Brett) to clean up the diacetyl.

As for the barrel causing it from pedio or even sacchro, I wondered that too, but I would have thought they'd pitch a significant amount of Brett in Batch 60 (if they're claiming it's 100% Brett) that the existing barrel bugs wouldn't be able to produce more diacetyl than the Brett could clean up. Also doesn't explain why the entire batch wouldn't have the same issues if they used a single foeder like they do with St. Bretta & Surette (and Vielle & Hop Savant). Or maybe alll batches do have the same issues, just the small <1% are under the wrong conditions for the wrong amount of time?

I really have no idea what the issues are around it, but it considering it's such a small amount of bottles I'd figure it has to do with how it's stored or bottled after fermentation is complete.

And simply put I think Chad had said it best, "they're sours." They are difficult to make sure 100% bottles taste the same without going the route of pasteurizing (and then priming with small amount of live yeast) before bottling like NBB & Boulevard.

 

Thanks for the answers, guys. Now, the question is: When you prime with live yeast, as in the case with NBB, does this yeast do anything to the beer other than convert the residual fermentable sugars to carbonation, as designed?

 

I don't see why it would if they used a neutral ale yeast.

 

So for those of us with some Batch 60s sitting around...what is the recommendation? Put them at room temp for a few weeks and shake them up every once in a while? I've got 2, one in the cellar and one in the fridge, and I don't feel like wasting them if there is some way to make the issue go away. Or just drink them asap before they get worse?

 

From what I understand, and please correct me if I'm wrong fellas... leaving them at room temp for an extended period of time (how long, I don't know) is the best way to clear up any potential diacetyl issues...

 

I can't see it getting any worse. If anything, they'll improve; maybe with a different flavor. Weird how some had this problem while others did not. Maybe some bottles were "unclean" or something. But if there's Bret in the bottle, then keep 'em at cellar/room temp to that yeast a-cookin. No need to "shake", maybe tip it horizontal once, then back upright.

 

Still yet to come across a bad batch 60. Think things are getting exaggerated a bit.

 

The yeast need to be active to clean things up, so room temp is the best bet. If the bottle is in the fridge, swirl the bottle like odell suggests with easy street to bring the yeast back into suspension and let it sit at room temp also. Depending on how bad the diacetyl issue is it could take weeks to clean up. But, in the case of batch 60, warmer temps mean hop volatiles breaking down faster. (Insert trumpet fail here)