WTF!!! Diacetyl in all my beers!

I brewed a dead guy ale wjich tasted great during bottling, ended up tasting like butterscotch. Ive recently done two batches, an apa and a porter. Before i begin i should mention that the apa has only been in the bottle three days and the porter only five. But i was exited to taste my apa because at bottling time it had a great taste, which now tastes of buttescotch. The porter actually tasted pretty damn good except it had a medium butterscotch flaver in the background. Im a little pissed because every one of the four batches ive done has tasted great at bottling time but ended up not tasting very good. I feel like im being sanitary enough, for the first three batches i soaked the bottles in bleach and scrubbed them with a bottle brush, rinsed them out about four times each, soaked them in star san and covered them with caps soaked in star san until bottling time( ~10 mins after star san soak). I wash everything out well using hot water amd a sponge making sure to get every square cm of everything and use star san on everything. WTF! Dear beer gods, sometimes i think you might not exist. But just in case, heres a prayer - please let my beer end up tasting ffffffffffing good. Dont let me keep making butterscotch drink. There. Thats it.

Its probably not the sanitation but the fermentation.

Diacetyl can be caused by a bacterial infection, but usually it's the result of a bad lager fermentation. Not something you normally see in an ale fermentation because of the much higher temperatures.

What probably happened was that you had a lot of diacetyl precursors (alpha-acetolactate) in your beer that over time chemically turned into diacetyl. So you won't taste diacetyl as first, but as it converts to diacetyl, the ppm rises until it either runs out of the precursor or you hit the flavor threshold, which your beer seems to have done. This is where the diacetyl rest we associate with lagers comes into play, as the yeast will reabsorb the diacetyl and turn it into acetoin and then 2,3-butanediol, which have a really high flavor threshold. The process is accelerated at higher temperatures and should be done while the beer is still in the primary with all those yeast.

How long did you let your beer sit in the primary? Was your yeast strain particularly flocculant?

Well its been 4 different kinds of yeast. Muntons premium, wyeast pacman, wyeast irish ale, and nottingham. The first one(muntons) didnt have any diacetyl flavor. I tried to keep temps down on the second two(irish ale and nottingham) by using an ice bath - the temps never got above 68. I know that the porter and apa should taste better as they condition. But its a little disheartening to have four batches taste funky. My first batch was oxidised. The porter will taste fine after a bit because it has some good roasty/chocolate flavors to hide behind but not the other beers.

Did you boil the wort with the lid on your kettle? That can be a cause of diacetyl. You need to boil off the precursors to diacetyl and with the lid on, these condense on the lid and drip back into the wort. This could also be a problem if you didn't get a rolling boil or if you cut your boil short.

Please describe your brewing process. It would also help to know what strain of yeast you were using. Are you rapidly chilling?

Diacetyl is a natural by product of fermentation. Given time, when the yeast is done with its fermentation work, it will actually re-absorb the diacetyl from the beer. It can also be produced by bacteria.

Give the bottled batches some time, a week or three. That flavor should diminish to some degree.

RM-MN said:

Did you boil the wort with the lid on your kettle? That can be a cause of diacetyl. You need to boil off the precursors to diacetyl and with the lid on, these condense on the lid and drip back into the wort. This could also be a problem if you didn't get a rolling boil or if you cut your boil short.

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Really? I have always put a lid on during the boil. Interesting to hear this though.

Did you perform a diacetyl rest period? What temp are you storing your beers to carb up?

RM-MN said:

Did you boil the wort with the lid on your kettle? That can be a cause of diacetyl. You need to boil off the precursors to diacetyl and with the lid on, these condense on the lid and drip back into the wort. This could also be a problem if you didn't get a rolling boil or if you cut your boil short.

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Are you sure you're not referring to DMS? I thought diacetyl was strictly a product of fermentation.

from the morebeer site:

Diacetyl: A fermentation by-product that tastes and smells like butter or butterscotch. All yeast produce diacetyl and different amounts of diacetyl depending on the strain. The trick is pitching enough healthy yeast so it reabsorbs its natural waste. Most homebrewers rush fermentation because they don't see any activity or bubbles in their airlock. Patience makes great beer. If you can let your beer go an extra 5-7 days after you think it has completed fermentation the better off you are and your beer will taste cleaner. Temperature control is a key factor too in controlling diacetyl flavors. If you stress your yeast with inconsistent temperatures they will get tired and either die or go to sleep on you and will not beable to reabsorb their waste. If you're fermenting lagers a 'diacetyl rest' is important but not required to eliminate the butter flavor. Diacetyl can also be caused by contamination which becomes more noticeably as beer ages. Usually a haze that never goes away is a sign of contamination.

Diacetyl Rest: Raising your fermentation temperature 4-8 degrees above your set temperature to help your last surviving yeast to reabsorb its diacetyl production. A 4-7 day diacetyl rest is usally enough time to rid of all buttery flavors. INSIDE TIP: A yeast like our Whitelabs 833 at 48-50F has no diacetyl flavors after 6 weeks in the primary fermenter and does not need diacetyl rest. But our Czech Budejovice yeast still has a lot of diacetyl after 6 weeks in the primary fermenter and it needs a 7-14 day rest at 55-58F to eliminate any buttery flavors or aromas. Know your yeast and you will be rewarded.

RM-MN said:

Did you boil the wort with the lid on your kettle? That can be a cause of diacetyl. You need to boil off the precursors to diacetyl and with the lid on, these condense on the lid and drip back into the wort. This could also be a problem if you didn't get a rolling boil or if you cut your boil short.

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RugerRedhawk said:

Really? I have always put a lid on during the boil. Interesting to hear this though.

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ThePearsonFam said:

Are you sure you're not referring to DMS? I thought diacetyl was strictly a product of fermentation.

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You definitely don't want to boil with your lid on! But it doesn't cause diaceytl- it causes DMS (cooked cabbage or a vegetal flavor).

Diacetyl is usually yeast related, but can also be a sign of pediococcus infection.

Before I did anything I would let the beer condition. MUCH can, and usualy does change over the course of three weeks. Checking the taste durring the process is a valuable tool but you need to wait more than 3 to 5 days to know what you will finally have.

Could just be an effect of bottle conditioning and the carbing process in the bottle. Most likely, it's somethign to do with your normal fermentation.

There's a pretty good chance that it will clear up wit ha bit more time, but if not let the beers warm up, give them a swirl and wait a week. Try get to get some those yeast active again to clean that up some.


I'd say to make sure that you pitch large starters next time. Get enough healthy yeast on there to quickly clean up the diatecyl when fermentation is complete.

kaiser423 said:

I'd say to make sure that you pitch large starters next time. Get enough healthy yeast on there to quickly clean up the diatecyl when fermentation is complete.

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If I may... not so much "large" starters but appropriately sized starters.

ThePearsonFam said:

If I may... not so much "large" starters but appropriately sized starters.

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My point was that he might be having some yeast viability issues if he's getting so much diacetyl so often. With that in mind, an appropriately sized starter might still be under-pitching. So it might be worthwhile to try making a starter on the larger side to see if things go away.

This is, of course, assuming that he's making a starter at all It could be that some of his dry yeast was old, or something.

My bet is still that time will fix it, but if he wants to try something, try increasing yeast cell count.

I'm still interested in seeing how long he had the beer in the primary. Racking too early could definitely contribute off flavors. Especially with a more flocculant yeast.

With the apa and the porter being in bottles 3 and 5 days, I would think that there would be active fermentation (for carbonation) going on. So, wouldn't that produce diacetyl? To me, it would seem that you need to wait on these two to get an idea of what the final taste is going to be.

Well my dead guy clone has been in the bottle for almost 6 weeks now. The other two will hopefully clean up while still carbonating. And as for how long they were in primary - the dead guy 15 days, the porter 19 days, and the apa 15 days. Both the dead guy and the apa have chill haze which is actually kind of cool to see the difference in them from when theyre poured till they warm up. I do boil with the lid on but slightly cracked - so theres something to fix right there. I boil with the lid because my wort wont boil without it holding in some heat. Maybe i could reduce my boil size. I cool the wort in a sink ice water bath and i think another place to improve would be to aerate better. I pour my cooled wort through a sanitzed strainer to pick up whatever might be floating loose in there(irish moss, runnaway hop material) and to help with aeration. I top it off with distilled water (i use tap water for the boil). Ill then stir around for a couple of seconds and put the lid on till i pitch the yeast and then stir a little bit more. Im thinking that after i top it off with water i should use a sanitized wisk and go to town for a minute or so. Any other ideas in where i might have gone wrong or ways that i might improve.

I should also mention that i used one wyeast smack pack for both the dead guy and the porter - no starter. The packs say theyre good up 1.060 og. Thats about what the dead guy was and because of a misunderstanding between the guy at the lhbs and myself about how much lme extract i needed the porter og was 1.040 (target og = 1.058) well within the means of a smack pack. The apa was done with 1 packet of nottingham and had a og of 1.048. The fermometer on the apa bucket read between 62 and 64(i think) during initial fermentation. When the airlock activity slowed down i let it warm up a bit and when airlock activity stopped i let it sit at about 68-70 on the fermometer.

15 days is pretty short in the primary. I leave my beers in the primary at least a month. It gives the yeast plenty of time to clean up some off flavors.