[reverseapachemaster]

Disappointed with this IPA that developed a substantial amount of diacetyl in the bottle, not sure what went on here. It's my first attempt at an IPA, so I don't know if I'm missing something here.

Black IPA, nothing too crazy here. I fermented it with S04 at 61F for seven days and reached terminal gravity. Let it rise to room temperature (low 70s) for three days. Then cold crashed as cold as I can get it with my equipment (around 40F). Transferred to bottling bucket to dry hop away from the yeast. Transferred the beer cold, using my normal racking equipment. Dry hopped at room temperature for five days with the hops in a hop sack. Removed sack, added priming sugar and bottled as normal. Bottle conditioned at room temperature for two weeks.

Tasted beer at bottling, no diacetyl present. Beer properly carbonated but there is a strong amount of diacetyl present. I didn't perform a FFT but to get that much diacetyl in the bottle I assume it would have been present at least a little in the tasting at bottling. My wife is extremely sensitive to diacetyl and she didn't detect any at bottling either.

Thoughts on causes? I have fermented S04 at those temperatures using this same process at least ten times with no diacetyl issues in the beer. I've also dry hopped using this same process with no diacetyl problems. No appearance of infection in the bottle. No pellicle in the bottle. No unusual haze or off texture to the beer (except the diacetyl). No sourness. No other off flavors detected.

Thoughts on remedies, if any? I know time may help the yeast in the bottle absorb the diacetyl but there's a lot of diacetyl stuck around and I'm not exactly thrilled to let an IPA age out. If time is my only remedy, am I better off letting the yeast clean up at room temperature or shove the bottles in the fridge and let the cold work its magic on diacetyl like one would a lager?

[denny]

The only thing I can think of is infection.  If it was a fermentation issue, it would have been there when you bottled.

[hopfenundmalz]

The diacetyl precursor can oxidize to diacetyl. This has happened to me.

[majorvices]

The diacetyl precursor can oxidize to diacetyl. This has happened to me.

+1 and this and Denny. If you didn't taste diacetyl prior to bottling it is one or the other and very likely the latter. Unfortunately the techniques most homebrewers use to rack and bottle beer inevitably introduces oxidation.

[Wesbrau]

If it's not an infection, but merely precursor oxidizing to diacetyl, next time you could let the ferment temp rise before you hit terminal gravity. That will keep the yeast working faster and longer.  61F is pretty cold.  You could also try the forced diacetyl test described in the White and Zainasheff Yeast book.  That will let you know if you have too much precursor before bottling.  If so, you wait longer to let the yeast finish up. 

[majorvices]

If it's not an infection, but merely precursor oxidizing to diacetyl, next time you could let the ferment temp rise before you hit terminal gravity. That will keep the yeast working faster and longer.  61F is pretty cold.  You could also try the forced diacetyl test described in the White and Zainasheff Yeast book.  That will let you know if you have too much precursor before bottling.  If so, you wait longer to let the yeast finish up.

I'm not sure a diactyl rest can work to clean up the precursors to diacetyl, though certainly they can clean diacetyl already present. That said, I always let my fermentation temp rise near the end.

[davidgzach]

If it's not an infection, but merely precursor oxidizing to diacetyl, next time you could let the ferment temp rise before you hit terminal gravity. That will keep the yeast working faster and longer.  61F is pretty cold.  You could also try the forced diacetyl test described in the White and Zainasheff Yeast book.  That will let you know if you have too much precursor before bottling.  If so, you wait longer to let the yeast finish up.

I'm not sure a diactyl rest can work to clean up the precursors to diacetyl, though certainly they can clean diacetyl already present. That said, I always let my fermentation temp rise near the end.

+1 Keith. 

[reverseapachemaster]

I think the issue may have been in not ramping up fermentation temperatures like I normally do. Usually I get up into the upper 60s by day 4-5 to push clean up but I got busy with work that week and forgot to drive up temperatures. Add in the oxygen from bottling and that's diacetyl.

Ok so any hope of salvaging these beers?

[erockrph]

No experience with it myself, but maybe the yeast left in the bottle may clean it up given enough time and the right conditions? Try warming the bottles up and rouse them every day or two. Give them a week or two and taste to see if the diacetyl is getting cleaned up.

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[udubdawg]

two weeks since bottling?  If so I'd give it one more week before I became concerned.

[beersk]

This happened to a friend of mine. It tasted fine at bottling, but after a couple weeks he a got a butterscotch bomb. It went away after a few more weeks in the bottle. I think it was from fluctuating fermentation temps he had in his basement. Add in a little oxidation at bottling and there you go. Give it time, it'll go away.