Diacetyl Woes (Advice Please?)

[Coffeeturnal]

I've been using RVA 104 Hoptopper yeast (Conan). Definitely not going to be using it anymore for a couple of reasons.

On the first batch (an IPA), it crapped out early. It was predicted to end at 1.014 and it stopped at 1.018. In the past I'd had a couple problems with mash temperature, so I chalked it up to that and bottled (it had been 2.5 weeks). It would not carbonate at all, though it did produce a LOT of diacetyl.... Finally after heating it up to the high 70s and shaking the bottles to get the yeast in suspension it carbonated. And finished fermenting down to 1.014 and didn't do anything about the diacetyl. Now I had to dump the entire batch of gushers that were yeasty diacetyl bombs.

Note that I did a diacetyl rest in the lower 70s.

Prior to realizing this issue I pitched some that I saved into a stout (very large pitch, don't remember exact numbers but was slightly larger than calculators said I needed). With an OG of 1.090, I've left it in primary for a while for some bulk aging (it's been there a month now). It has an estimated FG of 1.016 but it seems to be stuck at 1.021 now. It actually tastes really good as is, but I don't want to have the same issue as last time. I did a diacetyl rest in the upper 70s this time.

I just did a forced diacetyl test today (I was hoping to bottle tomorrow). The level present after the test made it completely undrinkable... What do I do?

I did a little googling and saw some people suggest that krausening can help clean it up. Since I've found that this yeast doesn't actually like to clean up the diacetyl, I'm hesitant to use it for that purpose. I have a packet of US-05 and one of S-33 in the fridge that I could use. Would either of those work for cleaning it up? According to brewers friend, US-05 would probably take it down to 1.015. That's a littler drier than I wanted it, but might be a small price to pay for saving the batch.

Any advice for proceeding? I'd really like to not have to dump two batches in a row...

 

[GnenieGone]

Just checking for understanding. Do you sample right after fermentation, then again after dry hop?

 

[Coffeeturnal]

Yes. Also, there were 7 days in between dry hop and bottling.

 

[GnenieGone]

Was there diacetyl present after primary fermentation?

 

[Coffeeturnal]

No, it didn't appear until after bottling.

The stout does not have any diacetyl present yet either. But it was overwhelming after a forced diacetyl test on a sample.

 

[GnenieGone]

You have been bitten by the dreaded post fermentation diacetyl bug. This is a refermentation caused by carbs in the hops during dry hopping, usually very high amounts. It usually becomes noticeable after day 3 or 4 of bottling/kegging. Apparently you're ultra sensitive to diacetyl which makes it a PIA for us.

 

[Coffeeturnal]

Is there anything I can do to clean it up? I didn't dry hop the stout, so it must have come from the primary fermentation.

Maybe warm the fermenter and then pitch a rehydrated packet of US-05?

Yeah, I've found recently that I'm super sensitive to diacetyl... Unfortunate

 

[GnenieGone]

Unfortunately there's not a damn you can do about your current batches...that I'm aware of. There are many of us here with the same problem and we've recently came up with solutuons moving forward.

1) Add most if not all dry hops during day 2 or 3 of fermentation. This will allow any diacetyl formation to be "eaten up".
2) Allow 2 weeks (some will argue) min to ferment out and trub to form.
3) Cold Crash for 2 days to get as much yeast out of suspension.
4) Eliminate beer seeing any oxygen during transfers. Bottling is there for an inherent problem.

 

[GnenieGone]

I used to brew decent IPAs and those suggestions I mentioned worked pretty well even bottling. It wasn't until I started NEIPAs and attempting grain to glass in 7days that everything got mucked up. So I've seen both sides of the coin.

 

[GnenieGone]

Anyway I'll report back. Here's my next attempt mashing now, with those suggestions. Also, bought a Fermentasaurous for no oxygen transfers to keg.

Cheers!

 

[GnenieGone]

Is there anything I can do to clean it up? I didn't dry hop the stout, so it must have come from the primary fermentation.

Maybe warm the fermenter and then pitch a rehydrated packet of US-05?

Yeah, I've found recently that I'm super sensitive to diacetyl... Unfortunate

IDK. To do that process, I'd actually add a pound or 2 of dme. You should 1000x more yeast then needed right now. You need very active yeast to clean up diacetyl and probably have to reoxygenate also.

 

[MaxStout]

Another vector for diacetyl can be a pedio infection. Replace things like plastic tubing, and make sure your sanitation regimen is up to snuff. Your bottles should be thoroughly clean, then sanitized.

I feel for you. I had a couple butterbombs a few years ago, and the problem ended when I stepped up sanitation. I replaced tubing every couple of brews (cheap fix) and make sure bottling bucket (and the spigot!) are clean and sanitary.

 

[Smellyglove]

If you still have diacetyl-potential-bombs in the fermentor, after an adequate fermentation time, heat them up, and/or give them a krausen, and keep it "hot". If the beer sucks in the fermentor right now, do a hefty DME solution, and pitch a whatever yeast you have into it, and pitch it at high krausen, should take a few hours after pitch to reach high krausen, get that stuff into the fermentor.

 

[Coffeeturnal]

Unfortunately there's not a damn you can do about your current batches...that I'm aware of. There are many of us here with the same problem and we've recently came up with solutuons moving forward.

1) Add most if not all dry hops during day 2 or 3 of fermentation. This will allow any diacetyl formation to be "eaten up".
2) Allow 2 weeks (some will argue) min to ferment out and trub to form.
3) Cold Crash for 2 days to get as much yeast out of suspension.
4) Eliminate beer seeing any oxygen during transfers. Bottling is there for an inherent problem.

I definitely did step 1 and 2 on the IPA. I don't have means to do a cold crash at the moment. Unfortunately, bottling is my only option at the moment as well. I might look into kegging once I'm done with grad school, but right now with a pending move next year (when I'm done) it doesn't make a whole lot of logistical sense to get large equipment that I would want to bring with me.

Anyway I'll report back. Here's my next attempt mashing now, with those suggestions. Also, bought a Fermentasaurous for no oxygen transfers to keg.

Cheers!

Fun! What are you making?

Another vector for diacetyl can be a pedio infection. Replace things like plastic tubing, and make sure your sanitation regimen is up to snuff. Your bottles should be thoroughly clean, then sanitized.

I feel for you. I had a couple butterbombs a few years ago, and the problem ended when I stepped up sanitation. I replaced tubing every couple of brews (cheap fix) and make sure bottling bucket (and the spigot!) are clean and sanitary.

Thankfully, I am pretty confident that this isn't an infection issue. My understanding is that if it were an infection, the diacetyl presence would be increasing as the infection continued. Is this correct?
The diacetyl didn't seem to increase or decrease at all with time.
I've gone to great lengths to ensure that everything is as clean as possible after a couple of lacto infections about 6 months ago.

If you still have diacetyl-potential-bombs in the fermentor, after an adequate fermentation time, heat them up, and/or give them a krausen, and keep it "hot". If the beer sucks in the fermentor right now, do a hefty DME solution, and pitch a whatever yeast you have into it, and pitch it at high krausen, should take a few hours after pitch to reach high krausen, get that stuff into the fermentor.

Right now the stout is diacetyl-potential after a month in primary. It's still in there. I'm going to try to warm it up as much as I can and then maybe pitch US-05. The one other time I've gotten diacetyl was with US-05, but it was very quick about cleaning it up. I'm hoping that I can utilize that property on this one. I was planning a trip to the homebrew store tomorrow anyway, so I'll pick up some DME while I'm there.

 

[GnenieGone]

I definitely did step 1 and 2 on the IPA. I don't have means to do a cold crash at the moment. Unfortunately, bottling is my only option at the moment as well. I might look into kegging once I'm done with grad school, but right now with a pending move next year (when I'm done) it doesn't make a whole lot of logistical sense to get large equipment that I would want to bring with me.

Fun! What are you making?

I agree is not an infection. Your a spitting image of my brewing. Stouts/quads or anything non hoppy are great. It's only high hopped beers..which is a clue.

Cold crash is as simple as buying a $5 tub and adding ice every 4hrs or so.

I'm making a latest IPA batch. Last one, 1st in the Fermentasaurous, was fine except for Phenols which was probably due to high mash pH. BUT NO DIACETYL!! [emoji106]Taking care I'm at 5.3 with mash this time.

 

[Smellyglove]

I definitely did step 1 and 2 on the IPA. I don't have means to do a cold crash at the moment. Unfortunately, bottling is my only option at the moment as well. I might look into kegging once I'm done with grad school, but right now with a pending move next year (when I'm done) it doesn't make a whole lot of logistical sense to get large equipment that I would want to bring with me.



Fun! What are you making?



Thankfully, I am pretty confident that this isn't an infection issue. My understanding is that if it were an infection, the diacetyl presence would be increasing as the infection continued. Is this correct?
The diacetyl didn't seem to increase or decrease at all with time.
I've gone to great lengths to ensure that everything is as clean as possible after a couple of lacto infections about 6 months ago.



Right now the stout is diacetyl-potential after a month in primary. It's still in there. I'm going to try to warm it up as much as I can and then maybe pitch US-05. The one other time I've gotten diacetyl was with US-05, but it was very quick about cleaning it up. I'm hoping that I can utilize that property on this one. I was planning a trip to the homebrew store tomorrow anyway, so I'll pick up some DME while I'm there.

Not to be rude, but you must have quite poor yeast management or teperature control if you get diacetyl with us-05.

 

[Coffeeturnal]

Not to be rude, but you must have quite poor yeast management or teperature control if you get diacetyl with us-05.

Yeah, that was when I was starting out and just shoved it in a closet and didn't monitor anything. I had also gotten hasty and opened the bottle 4 days after bottling. The diacetyl had been produced from the fermentation of carbonating sugar and I hadn't given it ample time to clean up. By the time it was actually carbonated all of the diacetyl was completely gone.

I still don't have the best temperature control (large equipment when I have a move on the horizon), but I do monitor more and do what I can to make adjustments.

 

[GnenieGone]

**** ton of talk about this issue a while back on the NEIPA thread if you're interested. Kinda where I learned..

 

[Vale71]

Funnily enough, yeast does not produce diacetyl at all. What it produces are diacetyl-precursors, which we normally cannot taste as they have a very high taste threshold. Precursors that make it into the beer will then oxidize to actual diacetyl, and this explains while diacetyl can appear to "form" long after fermentation has finished, without invoking unfounded and bizarre "dry-hopping effect theories". This is a simple chemical process that will progress faster if beer is matured warm.
Most strains will reabsorb precursors even before they turn to actual diacetyl and become detectable by tasters, but some strains are very slow at re-absorbing and/or flocculate prematurely (just like the OP observed every time in affected batches) and then fail to fully clean up the precursors, which then turn to actual diacetyl. I've had such issues in the past with British strains from WLP which I then stopped using for this and other reasons (instability after packaging).
Kräusening with another strain is probably your best bet at cleaning up your failed batches.

P.S. Here is some reading material: https://beerandbrewing.com/dictionary/OFH8CHBicP/

 

[GnenieGone]

Great read^^^ @Vale71

Moving back to the way I used to brew IPAs which included 14-17 day fermentation and using 05. I have a buddy even more sensitive then I for diacetyl. He was my measuring stick. Allthough a bit would come through now and then I'd say 80% of my brews were free of it.

Guess it makes sense exposing the quickly finished beer to air is a killer also. Thanks!

 

[Vale71]

BTW I've been able to detect diacetyl in a blind taste at half of the accepeted taste threshold of 0.12 ppm, so I am a sort of human diacetyl detector too. Maybe that explains why I love diacetyl-laden beers like Pilsner Urquell.

 

[GnenieGone]

That would be a neat test to take. I taste diacetyl in more retail ipa/neipas then I care to say when other's have not. I usually chalk it up to taste buds confusing certain hop combinations...but think that's just me being nice.

 

[Coffeeturnal]

An update:

I pitched some US-05 yesterday (did a vitality starter to ensure the yeast didn't get too shocked by the 9% ABV) and it is well on its way to successfully cleaning up the diacetyl. I just did a forced diacetyl test again and it is near completely gone. I still detect is ever so slightly, but nowhere close to where it was before. I'm going to give it a bit more time to clean up, but even if it were to not clean up beyond this point I'd call it a win.

I'm really happy with this right now and now have a new trick in my toolkit should this problem ever pop up again.

 

[GnenieGone]

Nice Job! Thanks for the update. Wonder why the zillions of yeast cells already present didnt do their job..

 

[Coffeeturnal]

My suspicion is that this is just a lazy version of Conan since it did it in two batches. Oh well.

I liked the yeast, but I didn't love it. So I'm not too heartbroken about beginning to look for something else.

 

[snowtiger1987]

I wished I liked the taste of diacetyl. I am a human taste detector for it too. I can smell it from across the room if someone opens a bottle of beer that has it.

I recently had it develop in half of a batch of Brut IPA. I fermented in primary for 14 days then dry-hopped into 2 - 5 gallons carboys (purged with CO2). I cold-crashed and kegged the first carboy after 5 days in the secondary. No diacetyl in that one at all. After 3 weeks or so I did the same for the 2nd carboy. That one has diacetyl. I used the same cleaning and sanitation regiment for everything.

 

[Vale71]

No diacetyl in that one at all. After 3 weeks or so I did the same for the 2nd carboy. That one has diacetyl. I used the same cleaning and sanitation regiment for everything.

Again, just because you can't smell or taste diacetyl does not mean that the beer is not bursting to the brim with diacetyl precursors. As a matter of fact, since yeast does not put out actual diacetyl but only precursors, to get lots of diacetyl in beer you must start out with lots of precursors and then wait for those to evolve into actual diacetyl. Since this process is temperature dependent it might just be the case that you slowed this process down in your cold-crashed and cold stored beer so much that you can't detect diacetyl yet, which does not mean that you won't start tasting it somewhere down the line.
As an example, if you take the tour of the Pilsen Urquell Brewery in Plzen (that's how you're supposed to write it, Czech suffers from a serious chronical vowel deficiency ) they will take you down to the cellar where you get to taste their beer straight from old-stile casks. That beer has been stored cold all the time and there is absolutely no detectable diacetyl. The very same beer if run through the pasteurization process will instantly (actually, it takes several hours for the beer to be at room temperature again) develop the diacetyl-bomb character this beer is well-known for.

 

[ScrewyBrewer]

Once you get your fermentation temperature under control after a week increase the temperature .5F daily for 6 days then cold crash. This will give the yeast time to neutralize any off flavors.

 

[couchsending]

Conan can be a really hard yeast to use. Depending on where you get it from it can be really hit and miss. I personally don’t bother with it any more. There are way better, way more consistent yeasts to use, especially for homebrewers when you don’t know pitch rates, have precise control over O2, temp, etc.

If you have issues with a fermentation it’s often not advisable to use that yeast again for another beer.

For those of you that are cold crashing, are you able to maintain positive head pressure with Co2 when doing so? Otherwise you’re just asking for a ton of O2 pickup which can cause all sorts of issues, especially with hoppy beers.

 

[Vale71]

For those of you that are cold crashing, are you able to maintain positive head pressure with Co2 when doing so? Otherwise you’re just asking for a ton of O2 pickup which can cause all sorts of issues, especially with hoppy beers.

I have a Unitank so the beer is fully carbed by the time I start slowly ramping down the temp.

 

[Wayne1]

Pro Brewers use ALDC at yeast pitch to prevent the precursors from forming. https://bsgcraftbrewing.com/Content/Images/uploaded/ALDC onesheet_web.pdf

 

[Coffeeturnal]

That sounds like a very useful product. Do you know if it's available on a homebrew level?

Pro Brewers use ALDC at yeast pitch to prevent the precursors from forming. https://bsgcraftbrewing.com/Content/Images/uploaded/ALDC onesheet_web.pdf

 

[IslandLizard]

Make sure the yeast starters were made properly and yeast is always pitched within 10F of wort temps (5F is even better). This is to prevent forming of petite mutants that cannot metabolize diacetyl, and may be a possible indication of stalled fermentations, especially in higher gravity beers.

I've read Conan strains can be finicky, so I'd definitely switch to another yeast to compare. Do you oxygenate your wort?

Although cleaning and sanitation were mentioned before, to eliminate another source of Pedio from the equation, pay some extra attention to cleaning and sanitizing valves and seals on your equipment, even the ones on your boil kettle.

Take the valves apart and clean and sanitize thoroughly, especially the spaces behind the ball. Over time a black sludge can develop in there loaded with Pedio. Even a gas heat source doesn't seem to get that valve area on a kettle hot enough to kill them. I take them apart around every 6-8 brews. I've only found the black slime in a 2-part kettle valve I had been using for 2-3 years and earlier inside my bottling bucket's spigot before I started kegging the majority of my beer. In those, the slime harbors in the narrow space between the two 3/4" plastic barrels that rotate within each other, and behind the rubber seals between the body and bucket, as well as in the threads.

 

[Wayne1]

That sounds like a very useful product. Do you know if it's available on a homebrew level?

To the best of my knowledge, it is available from Brewers Supply Group in the US. It is sold in a liter container. Gusmer also sells ALDC but in a minimum of 5 kilograms.

Perhaps some homebrew shop could purchase the liter container and repackage it in smaller quantities for homebrew use.

 

[ScrewyBrewer]

For those of you that are cold crashing, are you able to maintain positive head pressure with Co2 when doing so? Otherwise you’re just asking for a ton of O2 pickup which can cause all sorts of issues, especially with hoppy beers.

Fermenting 10 gallons of Amber Ale in a chest freezer for a week fills it with plenty of nostril burning Co2. More than enough to kill off any fruit flies that found their way inside it. I'm not worried at all about introducing O2 during cold crashing.

 

[Northern_Brewer]

Pro Brewers use ALDC at yeast pitch to prevent the precursors from forming. https://bsgcraftbrewing.com/Content/Images/uploaded/ALDC onesheet_web.pdf

I'd view ALDC as a last resort to clean up the last traces - and it tends not to be easily available in retail packs. So for instance Cloudwater use it, but they obsess over yeast health with eg zinc and nutrients, and start the diacetyl rest for their DIPA at 1.045 - see this blog (and other articles there), and the recipe linked therein.

 

[poley]

Aggressive dry hoppping can cause refermentation due to the enzymes present in hops. If you're doing a large dry hop addition, try adding it while you still have yeast in suspension to quickly chew up the new fermentables created from the enzymes in your hops. If you do not allow your fermentation to fully ferment out those new sugars, you could have bottle bombs. If you see fermentation kick back up, based on hydrometer readings, make sure you check for diacetyl again before crashing and packaging.

For more info, do some research on "dry hop creep".