Preventing Diacetyl -or- "Hold The Butter Please"

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Doog_Si_Reeb

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I believe it's less common, but you can also get diacetyl in ales. My first partial mash was a low gravity English Bitter. After it had finished bottle-conditioning, I noticed a strong butterscotch smell and flavor. It really pissed me off to say the least. One of my buddies, who drinks mostly BMC, told me "wow, this is like a butterscotch beer. It's really good." :mad: I wasn't impressed, however...

Oddly enough, over time in the bottle, the diacetyl has mostly disappeared. I even took some to a homebrew club meeting and it got good feedback, no one mentioned diacetyl.

Along these lines, I was talking to a professional brewer recently. He said he does a diacetyl rest on his ales too. He raises the temperature a few degrees and let's them sit slightly warmer for 2-3 days. I hadn't heard of that before, but his beers definitely don't have noticeable diacetyl.
 

Revvy

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I just dug up some more info on diacetyl that backs this thread up, along with the benefits of letting a beer sit on the yeast cake a bit longer.

I found this article;

"THE ROLE OF DIACETYL IN BEER
By Moritz Kallmeyer"

The Abstract begins...

Diacetyl as a product of fermentation is more characteristic of ales than lagers. Diacetyl is produced early in the fermentation, and then most of it is reabsorbed by the yeast and reduced to flavourless compounds later on. Yeast strains differ markedly in their diacetyl reduction ability. Some ales and a few lagers (such as the famous Pilsner Urquell) contain perceptible amounts of diacetyl, but as a rule modern brewers consider it as a fault. This is because certain bacterial infections and other errors in brewing technique will increase diacetyl levels resulting in unacceptable beer aroma and flavour profile. This parameter thus serves as a quality check. However, it is important to remember that diacetyl flavour is a natural by-product of yeast fermentation, and in some beer styles it is an optional or even required flavour component in low amounts.
From here....


Drayman's Brewery and Distillery

There's two methods of rests listed in the Kallmeyer article...one for ales and warmer beers....interesting.

Maturation of beer flavour requires the presence of yeast as a catalyst. There are many methods of finishing that have the sole objective of prolonging the contact of beer with yeast after primary fermentation is completed. I want to emphasize that a diacetyl rest with most of the yeast lying at the bottom of the tank and not enough in suspension is of no use. Most lager breweries, especially those that use Weinhenstephan 308 or similar “diacetyl producing yeast’s” employ a long diacetyl rest, in order to minimize diacetyl in the finished beer.

Method 1
If a very cold primary fermentation was used it involves allowing the beer temperature to rise from the controlled primary fermentation temperature of about 10°C to 15-18°C when the primary fermentation is coming to an end. Normally, the time is determined by the attenuation of the beer. If, for example the wort starting gravity was 1050 and the expected terminal gravity is 1010, then the diacetyl rest would be commenced when the beer has attenuated to about SG 1023 when two-thirds of the total fermentable material in the wort has been consumed. The diacetyl rest normally lasts for 48-72 hours, until primary fermentation is over and secondary fermentation is under way. At this time the temperature is lowered when the more traditional method is followed, probably 1°C per day until the lagering temperature of 0-1°C is reached.

Method 2
If a warmer primary fermentation temperature was used for ale or lager the diacetyl rest involves either lowering the beer temperature 2 or 3°C at the end of primary fermentation or keeping it constant for up to 6 days. In lager yeast strains with low diacetyl production it is common practise nowadays to employ a short diacetyl rest followed by centrifuging to remove excess yeast and then crash cooling to 0°C. When brewing ales, that should have very low diacetyl levels especially German Ales like Alt and Kölsch, the implications are to not use highly flocculent yeast and to allow an extended primary fermentation, albeit at cooler temperatures until sufficiently low diacetyl levels are reached. Yeast that settles in the cone is still removed on a daily basis.
Interesting for ALES one of the recomendations is to LOWER the temps a bit...or leave them at the same temp for 6 days...learns something new everyday...I'm going to have to try the cool rest.

It also backs up the idea of leaving beers on the yeastcake for awhile longer to allow the yeasts to clean up after themselves.

:mug:
 

ShortSnoutBrewing

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Bringing this one back to life for a minute. I've changed my process over the last year and a half to include a longer primary. Typically 3 - 4 weeks. Somehow I am still getting dinged in comps for Diacetyl. Should I leave the beers sit longer? Maybe it's a temp thing? What are the other options?
 
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Bringing this one back to life for a minute. I've changed my process over the last year and a half to include a longer primary. Typically 3 - 4 weeks. Somehow I am still getting dinged in comps for Diacetyl. Should I leave the beers sit longer? Maybe it's a temp thing? What are the other options?
I honestly think that "hints of slight diacetyl" is the go to flaw that wanna be judges lean on to show they know something.

Bullsh!t.

I had two competitions 4 weeks apart...submitted the same beer...three judges in one and two in the other...one judge out of the five used the "slight diacetyl" argument to ding me. The beer went on to win 2nd in APA's in the one comp.

Ain't no way this beer had diacetyl. It was an ALE. Pitched on a huge cake. Fermented like crazy...sat at 68 degrees for four weeks...oh...and did I mention it took a silver amongst 24 other APA's?

I'm coming to the realization that a church basement full of slightly intoxicated EAC wanna-be's will always result in someone trying to show their stuff and make some comment just to hear themselves talk.

In other words...if you don't detect diacetyl and you're doing everything right...I say ferk em.
 

G-E-R-M-A-N

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I honestly think that "hints of slight diacetyl" is the go to flaw that wanna be judges lean on to show they know something.

Bullsh!t.

I had two competitions 4 weeks apart...submitted the same beer...three judges in one and two in the other...one judge out of the five used the "slight diacetyl" argument to ding me. The beer went on to win 2nd in APA's in the one comp.

Ain't no way this beer had diacetyl. It was an ALE. Pitched on a huge cake. Fermented like crazy...sat at 68 degrees for four weeks...oh...and did I mention it took a silver amongst 24 other APA's?

I'm coming to the realization that a church basement full of slightly intoxicated EAC wanna-be's will always result in someone trying to show their stuff and make some comment just to hear themselves talk.

In other words...if you don't detect diacetyl and you're doing everything right...I say ferk em.
I can understand what your saying. I am sure there are some judges, that just dont have the proper taste buds for picking up flavors to judge with.
I am sure diacetyl is a common cop out for all the judges that want to act like they have a honed and refined pallet.


All in all if you know your beer is good screw them. I think I would go by what the majority said about it vs a few snobs.
 

WortMonger

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It seems to me that having the yeast suspended just after the majority of primary fermentation is finished. Could someone leave the fermenter sealed up and stir the yeast sediment with a stir-bar for faster maturation? Is this better accomplished after transfer to the lagering vessel? Is a lagering vessel even necessary, could you just do everything in one vessel if you were going to force carbonate after say a 6 week lager schedule?
 

DoblePartiGyle

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I recently attempted a Dreadnaught clone from "The Best of Brew Your Own" and it calls for fermentation with Wyeast 1968 English ESB yeast.

It's in bottles now, and it tastes pretty good, but there was definitely something "off" about it. I took it to my LHBS where they told me I had big diacetyl on it. I thought it might have been oxidized, but I'm sure it's diacetyl now, especially given Wyeast's admission of big diacetyl production: Wyeast Laboratories. London ESB Ale™ 1968
This problem is compounded by the yeast's high flocculation because the yeast falls out of suspension and hence isn't in contact with the beer long enough to get rid of the diacetyl present.

I brewed a second batch and transfered to secondary before I learned this stuff :cross:. Lesson learned: check out oddities of yeast strain used.
 

Brewinator

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Raising the dead thread, I have to say, I've had diacetyl problems with ales, and every time it is with US-05. My latest DIPA has this problem, and when you can smell something other than hops in a 200 IBU beer, you know you have problems.

I use dry yeasts because they start faster and I don't want to hassle with starters for various reasons. I might switch to S-04, or use Papazian's Cry Havoc, which seems to stay active a lot longer than most yeasts.

My experience has been that diacetyl doesn't go away with bottle conditioning. I guess there just isn't enough yeast at that point to clean up the mess.

I really am done with US-05. Interesting was this tidbit from Kallmeyer:

the implications are to not use highly flocculent yeast

US-05 is highly flocculent. I always thought that a positive, clearer beer, but now I wonder.



I recently attempted a Dreadnaught clone from "The Best of Brew Your Own" and it calls for fermentation with Wyeast 1968 English ESB yeast.

It's in bottles now, and it tastes pretty good, but there was definitely something "off" about it. I took it to my LHBS where they told me I had big diacetyl on it. I thought it might have been oxidized, but I'm sure it's diacetyl now, especially given Wyeast's admission of big diacetyl production: Wyeast Laboratories. London ESB Ale™ 1968
This problem is compounded by the yeast's high flocculation because the yeast falls out of suspension and hence isn't in contact with the beer long enough to get rid of the diacetyl present.

I brewed a second batch and transfered to secondary before I learned this stuff :cross:. Lesson learned: check out oddities of yeast strain used.
 

HenryHill

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I was drinking an IPA at the local Brewery last week, hanging out back waiting for the brewcrew to finish up so, we could pound beer in earnest, when the bottling leader called us over to inspect a couple of sankes of a light colored beer. It seems that he was concerned over the contents of the two kegs, and had set out glasses of each and a control one from the pub for us to sample.

One was completely, no question about it, like licking an ear of freshly buttered corn, the other only slighty, barely detectable, and the control, of course, was fine.

These were all the same beer, same batch. It became apparent that the affected beers were due to improper sanke cleaning as the control was of the same batch and kegged at the same time. Not sure if these were discovered by the pub and then rejected, but my point is to show that less than obvious things can affect the taste of a beer.

The one keg was dumped, the other, while not perfect, was good enough to still be served.
 

Matt Up North

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I was at a beer fest and had like 20 beers that had Diacetyl. I was shocked that people had that many beers affected by it.
 

delboy

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I honestly think that "hints of slight diacetyl" is the go to flaw that wanna be judges lean on to show they know something.

Bullsh!t.

I had two competitions 4 weeks apart...submitted the same beer...three judges in one and two in the other...one judge out of the five used the "slight diacetyl" argument to ding me. The beer went on to win 2nd in APA's in the one comp.

Ain't no way this beer had diacetyl. It was an ALE. Pitched on a huge cake. Fermented like crazy...sat at 68 degrees for four weeks...oh...and did I mention it took a silver amongst 24 other APA's?

I'm coming to the realization that a church basement full of slightly intoxicated EAC wanna-be's will always result in someone trying to show their stuff and make some comment just to hear themselves talk.

In other words...if you don't detect diacetyl and you're doing everything right...I say ferk em.

Diacetyl does seem to be the bogeyman of american homebrewing, in lots of english ales its not only present but highly desirable, at the right levels it dovetails beautifully with caramel and dark malts found in english ales.
The judges seem to be incapable of grasping this invariably labelling it as a flaw, maybe they shoud use their taste buds more and forget about what the guidelines say.
 

Pabst Blue Robot

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Diacetyl does seem to be the bogeyman of american homebrewing, in lots of english ales its not only present but highly desirable, at the right levels it dovetails beautifully with caramel and dark malts found in english ales.
The judges seem to be incapable of grasping this invariably labelling it as a flaw, maybe they shoud use their taste buds more and forget about what the guidelines say.

Agree 100%, Old Speckled Hen is a textbook example. The interplay between the caramel sweetness and the diacetyl really makes that beer, IMHO.
 

flyangler18

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Diacetyl does seem to be the bogeyman of american homebrewing, in lots of english ales its not only present but highly desirable, at the right levels it dovetails beautifully with caramel and dark malts found in english ales.
I'm not sure that I agree with this point. Low levels of diacetyl may indeed be present, but the toffee/butterscotch character that emerges in many English ales is more of an artifact from the malts than from the yeast character. The 'slickness' of diacetyl is most certainly distracting. It can be quite challenging to identify the source of a flavor as being yeast- or malt-derived.

As an example, the combination of Munich, the boil and aging can give darker Doppelbocks a moderately low grapey, pruney, or plummy character that may be incorrectly perceived as an ester from fermentation.
 

Yooper

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I do agree that diacetyl is a go-to off-flavor, though, for people looking for it.

I had a steam beer a couple of years ago that a judge said had diacetyl- leave it in primary longer, or something like that. Um, it was in primary four weeks, with a huge starter pitched, and then into secondary for lagering. There was not even a HINT of diacetyl. But, it did have a toasted quality with a warm undertone that he incorrectly identified as diacetyl, and a flaw.

I
 

flyangler18

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Another thing to consider is that diacetyl isn't just a yeast fermentation byproduct, it can also be generated by Pediococcus that might be lingering in unflushed beer lines for those bottling from the keg.

Pediococcus throws diacetyl in spades.
 

flyangler18

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I had a steam beer a couple of years ago that a judge said had diacetyl- leave it in primary longer, or something like that. Um, it was in primary four weeks, with a huge starter pitched, and then into secondary for lagering. There was not even a HINT of diacetyl. But, it did have a toasted quality with a warm undertone that he incorrectly identified as diacetyl, and a flaw.
I brewed a Wee Heavy using the traditional kettle caramelization technique, and the resultant toffee/caramelly flavors have been misidentified as diacetyl as well. For the times that I have truthfully detected diacetyl in beers, I immediately pick up on the slickness rather than the flavor and that's my litmus test.
 

Revvy

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Another thing to consider is that diacetyl isn't just a yeast fermentation byproduct, it can also be generated by Pediococcus that might be lingering in unflushed beer lines for those bottling from the keg.

Pediococcus throws diacetyl in spades.
I have noticed it big time in several bars where the only "decent" beer on tap was Killians. I have been to 4 different bars, two of them chains, where this was really noticeable. I agree about it being in bad tap lines, and I've always wondered if it comes out more in beers with more caramel/crytal malts.
 

Cpt_Kirks

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I have noticed it big time in several bars where the only "decent" beer on tap was Killians. I have been to 4 different bars, two of them chains, where this was really noticeable. I agree about it being in bad tap lines, and I've always wondered if it comes out more in beers with more caramel/crytal malts.
I think there was a thread on this...

I have seen diacetyl in Dos Equis Amber on tap. Same place did not have the diacetyl earlier, I guess they needed to clean their lines.
 

wstaufe

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Hmmmm- started out as a good info thread, but it seems that most posters are missing the point- how to AVOID diacetyl in the first place. It's true that some yeast strains exhibit more production than others, but the main culprit seems to be slightly warm fermentation temps. I wanted to scream when I saw the the posts about S-05...I've turned out countless batches of american ales pitched with it that have exhibited no diacetyl character at all.

HOWEVER...I recently produced two diacetyl bombs with Cooper's dry yeast- more my fault than the yeast though. I use a plate chiller with 10-gallon batches, but didn't notice that my tap water (city) is significantly warmer during the summer (I think the lines are fairly shallow in my area in SC). Instead of ~65F, my wort was finishing at ~90F :(
 

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I've been brewing since Aug 1994 and have never had a diacetyl problem...couldn't even fanthom a beer tasting like butter...until recently.

I had 2 brews in a row exhibit the "real butter" flavor.

One was a "speed brew" ale that started on Sunday, racked on Wednesday, and kegged on Saturday. I gassed it up and set it in the keezer for 1 week. Sample tasted like butter sure enough. I know how that one happened with that one, but can't explain the second one.

They're both good now...I took them out of the keezer, depressurized the kegs and added more yeast and an airlock and let them sit in the warm garage for another week or so until it corrected itself. ;)

Both were ales using Notty.

No more "speed brews" for me. :mug:
 

homebrewer_99

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The "speed brew" actually called for 2 packets of Notty...so that's what I used.

I know it's was because I took it off the yeast too soon (3 days). But that's what experimenting is all about.

The strange thing is, if I had not done a "speed brew" it would have been done by now anyway...;)
 

BeerAg

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I definately have a butter brew on my hands. Not overpowering, but I hate the mouthfeel. I think I am going to try the Nottingham trick to see if it will finish off the diacetyl. I am supposed to bring beer to a hunting trip in October, so I have plenty of time to let the beasties do their work.

What temp do you guys recommend?
 

Clayton

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I cant not think of one time I ever had a problem with diacetyl and i make 4 or 5 lagers a year, but there are two things i always do, 1. I am a shake-swerller about every other day i shake the carboy to get every thing moveing around and break up the cake, for the 7 to 10 days and then i do it once or twice on the second week i dont know why i just always have ,i will shake it one last time 2 days or so before the cold crash to the keg. and 2. I always leave my beer on the yeast atleast 2 weeks but most offton 3 to 4 , I am not in a hurry and have pleanty of space in my coolers to just let then do there thing.

so imho the trick beond all the other stuff stated in this thread is to not rush primary and give the carboy a good shake mixing up all the trub-yeast cake just before starting your diacetyl rest.
 

BeerAg

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Just an update.

After 2 weeks of Notty at about 70 degrees, one of the 2 kegs has cleared up almost completely, still a little green but should turn out fine. The other still has a hint of butter to it.

I am going to crash cool the good keg, and leave the other a bit longer. I am naming the beer Dead Orville (like Reddenbocker) Pale.
 

Sarrsipius

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So you skip the secondary completely? (which would give me a free 5g carboy). Any problems with getting sediment into the bottling process??
I have never used a secondary. I primary for 3-4 weeks and then bottle with little sediment in the final product. I've recently bought a keggerator conversion and am now going to go 3-4 weeks in the primary and then try 4-6 weeks secondary in the keg and then carbonate and serve from the same keg. If I don't notice a difference I'll just go 3-4 weeks primary and then rack to a keg and carbonate.

Never had a bad beer with up to a month in the primary.
 

pkgmsu2000

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yes, this thread is a bit old, but i am reviving it to say thanks for ALL of the helpful suggestions to cope with diacetyl.

it might be helpful to remind everyone about the role a yeast starter plays in this... i got this from a good friend that has been helping out a beginner brewer.

the first thing yeast does is reproduce. somehow, through the magic of life, it knows how many of them there are relative to how much food is available. Their darwinian response is to crowd out competition so if there is a ton of food (i.e. 5 gallons of wort) they will spend the first 8 to 12 hours just reproducing to the right ratio of Yeast to Sugar
Only then to they start to eat. The trouble for you the homebrewer is that the flavors they make reporducing aren't very good, aka butter amongst others... so if you "underpitch" they will need to really reproduce a ton in order to get to the point they are comfortable with but spending a lot of energy reproducing, they consequently produce a lot of diacetyl after they are done eating, but they will re-absorb a lot of the diacetyl. but the problem is, if your population is low, there won't be enough of them in the fermenter to re-absorb all the diacetyl they made. If that's the case, no amount of "clean up" time will make it go away. The easy solution is to just pitch more. The more that go in, the fewer generations they will need to build up to the proper population i.e. they make less diacytl in the first place, PLUS, you've got more of them to clean up so you win on both sides so you know you have a good batch
just do a small a starter, and make sure you don't contaminate it.
Good yeast + starter = guarenteed clean batch of beer
 

HoppedIPA

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You were not in Kansas city by chance were you.. I see you are currently in STL..?
I honestly think that "hints of slight diacetyl" is the go to flaw that wanna be judges lean on to show they know something.

Bullsh!t.

I had two competitions 4 weeks apart...submitted the same beer...three judges in one and two in the other...one judge out of the five used the "slight diacetyl" argument to ding me. The beer went on to win 2nd in APA's in the one comp.

Ain't no way this beer had diacetyl. It was an ALE. Pitched on a huge cake. Fermented like crazy...sat at 68 degrees for four weeks...oh...and did I mention it took a silver amongst 24 other APA's?

I'm coming to the realization that a church basement full of slightly intoxicated EAC wanna-be's will always result in someone trying to show their stuff and make some comment just to hear themselves talk.

In other words...if you don't detect diacetyl and you're doing everything right...I say ferk em.
 

Kealia

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I'm about to do my first lager and like everything else I've read a lot about this.
(Been brewing for about a year, just doing ales)

I'm doing a schwarzbier and pitching WLP810.
My plan was to ferment at about 55 for about a week, check gravity, and if I'm near the 75% done range then bring the temp up to about 65 for 3-4 days for the diacetyl rest. if it's not at that point, continue at 55 until it is.

Does that sound about right?

Likwise, after the diacetyl rest should I drop the temp back down to 55 (or colder) to lager for a while?

Final question - when it comes time to bottle, what temp do I use for the calculations? Fermenting temp (55) or room temp?

I appreciate any and all help.
I feel like I'm starting to brew all over again.
 

spillindillon

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this is hilarious because in my signature beer I put half a stick of butter in the wort. i believe beer is liquid bread so why not have toast. it compliments the hop bitterness perfectly but that's just me
 

Kealia

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this is hilarious because in my signature beer I put half a stick of butter in the wort. i believe beer is liquid bread so why not have toast. it compliments the hop bitterness perfectly but that's just me
I don't know if I should laugh or gag.
 

birvine

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This was an awesome thread - HBT is great for all of these pieces of excellent information.

B
 

kjjohns5

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Great thread.

I just had my first experience with diacetyl in a Middle Eastern inspired American Brown Ale. The beer itself is fantastic- really amazing, but when the beer warmed up there appears to be some definite diacetyl characteristics. I believe that I know what my issue was with this beer as I've never had this problem before.

Every beer I do will primary for at least 7 days, the most I've primaried was 2 weeks. I ALWAYS 2ndary my beer, and this case was no different. I pitched a massive and healthy yeast cake and the primary fermentation was vigorous and technically finished within 48 hours. I still let the beer sit for 8 days in the primary. I wracked into the 2ndary and it sat on a lb each of dates and raisons. Fermentation kicked up again, not crazy, but visibly active. After 1 week in the 2ndary I decided to bottle because I didn't want the beer to dry out any more (it was already 6.8%).

I realized, now that I'm drinking it, that my issue was likely not in primary, but rather in 2ndary fermentation. It seems that I bottled my beer too soon. When I added the sugar from the dates and the raisons, yeast became active, and fermentation had not stopped after 7 days in the 2ndary. Because I bottled with live, active yeast (granted, not as much as if it were in primary, which is likely why they diacetyl is not noticeable at cold temperatures) that had not had time to clean up after themselves.

I'm going to rebrew this beer soon but this time I'm actually going to wrack a 3rd time, off of the fruit, and let the beer settle for about 3 extra days. If my theory is correct, this will handle any diacetyl issues that I have.

I'll come back and update based on the rebrew of this beer, but in the meantime I'd like to ask if anyone has possibly had diacetyl issues from the 2ndary? I would suggest to anyone if you use fruit or anything that will kick up fermentation again, to plan for additional rest for you beer before you package.
 

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Red Deer, Alberta
I never had a problem with diacetyl, may be I just don't have enough experience yet. I'm fermenting my first lager right now using Pilsner Urquell 2001 it is at 1.020 after week and a half and it has no diacetyl or buttery taste to it. My process is always same for my ales, Kolsch or lagers. I make starter, re-hydrate if dry yeast or pitch lots of slurry. I always pitch cold regardless of what says on a pack of yeast and ferment at lower end for that yeast. I let it ferment 90% and then always bring it out of fermentation chamber to let it sit for couple days at room temperature (70-71F). Don't even know what diacetyl taste like
 
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