Diacetyl

I think what im getting is Diacetyl buttery and smooth mouthfeel. using us-05 mostly at 60 - 65 in a fridge but im getting it with any yeast i use. i tried leaving it in primary for 30 days with a diacetyl rest, tried 30 day secondary at 70F still get it. i cant taste it in samples, i dont seem to get it until 3 or 4 days in the keg. infection somewhere in my kegging system? i always sanitize kegs beer lines and taps with star san prior to kegging. im not very experienced in beer tasting or off flavors who wants to taste this and tell me for sure this is diacetyl?

I would guess you have an infection in the lines or taps somewhere. Especially since you are getting it after it's in the kegs. Diacetyl can be caused by infection. Have you pulled apart your taps and cleaned them? Try some beer line cleaner. Maybe you have beerstone in the lines?

Even without infection, diacetyl can occur after packaging. Diacetyl forms in fermented beer once the beer begins to oxidize. If you are getting oxygen into your system on the hot-side or post boil, diacetyl can appear in packaged beer even if you don't detect it when packaging.

Having said this, it sounds like you have a nasty case of it, and I agree with Mike that infection is a likely cause. Pediococcus bacteria is a common culprit.

FlyGuy said:

Even without infection, diacetyl can occur after packaging. Diacetyl forms in fermented beer once the beer begins to oxidize. If you are getting oxygen into your system on the hot-side or post boil, diacetyl can appear in packaged beer even if you don't detect it when packaging.

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Yes... the only thing I'll add is that this can occur from too much disturbance or splashing when transferring to secondary or the bottling bucket.

I had diacetyl in a keg once.

I just added about 1/4 of a packet of Nottingham dry yeast to the keg and let it sit at room temp for a week. It cleared it right up.

homebrewer_99 said:

I had diacetyl in a keg once.

I just added about 1/4 of a packet of Nottingham dry yeast to the keg and let it sit at room temp for a week. It cleared it right up.

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thats one thing ive never tried

shizzle said:

thats one thing ive never tried

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I have used US-05 the same way. Works great.

ill taste it for ya lol

update on this:
i tried fresh yeast on the keg for a week at 70 or so. tasted and smelled the beer before chilling and putting on gas and couldnt detect it. tasted it again after a day or so after it was chilled and on the gas still couldnt taste it. after 2 weeks on the gas in the fridge its back again. fyi i used a brand new hose and picnic tap. any ideas whats going on here?

shizzle said:

update on this:
i tried fresh yeast on the keg for a week at 70 or so. tasted and smelled the beer before chilling and putting on gas and couldnt detect it. tasted it again after a day or so after it was chilled and on the gas still couldnt taste it. after 2 weeks on the gas in the fridge its back again. fyi i used a brand new hose and picnic tap. any ideas whats going on here?

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Have you ever diasembled the fittings and cleaned those out? Could be some nasties hiding up in your popits.

maida7 said:

Have you ever diasembled the fittings and cleaned those out? Could be some nasties hiding up in your popits.

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yeah but i dont think i have since ive had this problem, will definately give that a try, any other ideas/explanations?

is it possible for a bacteria or wild yeast to live in 100% co2? as in the gas line or reg? the first batch i kegged i did the shake thing to carb it instantly. perhaps beer ran back into the co2 line although that was like a year ago and ive had many successful batches since. ive seen other threads with people having the same problem where the diacetyl is only detectable after packaging but havent seen anyone with a solution.

thanks for the replies and ideas

anything?..........................

I disassemble my posts for cleaning between every refill. There is always crud in them. That's probably where your problem is.