A diacetyl question

[scarer]

I suspect one of my current brews has diacetyl.

It has been in the keg for 2 weeks, 1 week at room temp and 1 week at 10-13C. It was in the fermenting bucket for 9 days but there was still a little movement in it so It is possible that I've taken it off the yeast too early.

Would it be beneficial to move the keg back into room temp for another week or so or would you suggest something more radical like adding more yeast to finish the job properly?

Any other suggestions welcome

Cheers.

[Barley Water]

First of all, a little diacetyl is not necessarily a bad thing (depending what style of beer we are talking about of course). A couple of strains I have experience with (Irish ale and Fullers) are known to throw it off while some strains don't so much. If your beer just has a hint of it, it will tend to make the beer more interesting, in my opinion. I will sometimes use one of these strains if I want a little of that flavor, say in a brown ale for instance. You can get a kind of buttered toffee flavor if you carmelize some wort in a beer like that. If however, the beer tastes like you are chewing on a big bag full of buttered popcorn, then yeah, I would say you have a problem.

If your beer just has a little, forget it and drink up. If on the other hand, you have the buttered popcorn effect, then maybe you can get rid of it by adding a neutral ale yeast. I would probably not bother unless the beer was really bad, in which case if the cure doesn't work you will end up tossing it anyway. Your post indicated that you know how to avoid the issue so just go a little slower next time. By the way, I was guilty of doing the same thing to a London Pride clone a few months ago, I just drank the beer because I kind of like the taste.

[prodigal2]

Hey scarer, how would you describe the flavour?

[scarer]

Buttery, but not too much so I couldn't drink it. Still nice and hoppy. The aroma is odd too.....

[scarer]

There are still a couple of weeks maturing to go and it isn't clear beer yet. It's not undrinkable but definitely noticeable after trying my Townes IPA that had a few more days on the yeast bed.

I used Nottingham yeast by the way and I've not had this taste before but I normally leave it to at least 10 days before kegging it. Just wondered if there was a remedy early on in the maturing phase rather than trying to sort it in a matured beer. Of course i've prob not helped by pulling off the sediment in testing/ tasting the beer!

[SteveD]

Not really. If it doesn't go with time just drink it, or tip it away if it's excessive. With diacetyl, prevention is better than cure. DO what you normally do and leave it on the primary yeast for a few days after fermentation has finished. I've left beer in the primary fermenter for up to a month with no ill effects, though two weeks is more usual. An added benefit of this extra time is dropping out excess yeast before kegging/bottling.

You could rack off the sediment when the fermentation is almost finished, say 2-3 points above where you expect it to end, and let it finish in a secondary FV. It can sit in there for ages and would clean up any diacetyl present. I often do that if I've got no cornies available to take the beer.

[stevezx7r]

I once made the mistake of thinking my beer (my first AG) had a diacetyl problem. Turned out to be a mix of the hops I used (EKG) and not being quite done when I removed it from the yeast bed (s04). After a few weeks the taste had gone although IIRC I'd drank most of it by then

[Martin the fish]

What does this diacetyl thing taste like?

[oblivious]

What does this diacetyl thing taste like?

some people describe it as butter/toffee butterscotch like

[booldawg]

Barley Water mentioned that caramelising a small quantity of wort would impart a buttered toffee flavour which would be appropriate for some beers. How many litres of wort would you boil down in a standard 23L brew length?

[scarer]

On this particular one I started off with 30lts and finished with 19.50lts post boil which was more evaporation than normal after 90mins, I diluted it with 2lts of filtered water in the fermenter. I normally end up with a litre more.

[mattmacleod]

I never rack beers to secondary and I think this helps me avoid diacetyl problems. I allow the beer to remain in the primary vessel until fermentation is complete (ie: consistent gravity reading for 3-5 days). As I understand it, a complete fermentation will allow the yeast to re-consume any diacetyl present. Once fermentation is complete, I cool the fermenter to allow the yeast to drop out and bottle or keg when the beer has dropped clear.

I know this raises the issue of yeast autolysis (sp?) but even when brewing lagers I rarely have the beer in the fermenter for more than four weeks.

[SteveD]

I once made the mistake of thinking my beer (my first AG) had a diacetyl problem. Turned out to be a mix of the hops I used (EKG) and not being quite done when I removed it from the yeast bed (s04). After a few weeks the taste had gone although IIRC I'd drank most of it by then

I don't think you made a mistake I doubt it was anything to do with the hop, assuming you're talking about a buttery, or butterscotch flavour...the bold line gives you a clue. SO4 tends to produce a lot of diacetyl, and if you take it off the the yeast before it's done, you're asking for it

There you go, Martin

[SteveD]

What does this diacetyl thing taste like?

some people describe it as butter/toffee butterscotch like

Careful...nowhere does it mention toffee in the flavour descriptors for diacetyl. Butter/butterscotch yes, but not toffee. We've had this discussion before, and if you have a caramel flavour from your malt, and get diacetyl as well, the combination could taste like toffee - but... diacetyl itself does not taste of toffee. It's a fine line as toffee tastes buttery - but the butter is the diacetyl, not the toffee/caramel

To illustrate, the same mistake on a more extreme level would be to say diacetyl tasted of garlic butter....if your diacetyl loaded beer was made with Garlic. (It has been done, In Brighton at least )

[scarer]

yeah i've def more butter than a toffee taste