Diacetyl from bottling

[Gristandgrain]

Hey guys,

This is now the second batch that I have noticed this, so I’m just curious if I’m starting to go crazy or not.

I’ve brewed two batches a little while ago, both are partial mash. First one being an ipa and second being a neipa style with fruit additions. Both were amazing in the keg and then upon bottling after a month or so to make room in the keg for new batch, a slick flavor of butter or butterscotch has definitely taken over. Or at least that is the flavor I am picking up because my wife doesn’t seem to notice anything like that as I do.

Both were hopped at some point with Citra hops and I feel that this might be the culprit but I just don’t know why I would be tasting the flavors after bottling something that’s been great in the keg for months prior. I also don’t think there is any oxidization issues because I’m fairly careful and haven’t noticed any diacetyl issues with any of my other brews.

I’ve never noticed these flavors in commercial Citra hopped IPAs before so I’m not really sure what to think. Maybe my diacetyl threshold is higher then normal? but I can’t figure out why I would notice it on these two beers and not the other ones..

 

[ESBrewer]

What is the yeast you are using? Oxygen (and heat) can definitely turn the precursor of diacetyl to actual diacetyl in the bottles. And some bacteria can produce diacetyl. To reduce diacetyl in bottles, add small amount of fresh yeast from a starter to the bottles (or use kräusening method, which is a bit more complicated). When the yeast is enough active & healthy and there is some priming sugars, it will eat the oxygen and also some diacetyl more effectively. During the primary fermentation, start at low and finish at high temperature. Heavy dry hopping can sometimes cause diacetyl.

 

[dmtaylor]

This is very common, especially in dry hopped beers. Some yeast strains cause it more than others. Residual yeast will eat the diacetyl over time if the bottles aren't kept ice-cold. In my experience this takes 3-4 weeks on average at moderate temperatures of like 55-70 F. Don't chill your bottles, give the yeast time to work, and the diacetyl should fade over time.

 

[IslandLizard]

I would drink it faster or brew smaller batches. 1 month is about the upper limit for home brewed IPAs and other hoppy beers. Bottling is not going to make them better, worse actually.

Look up how to 100% liquid pre-purge a keg, and fill through the liquid in post. Using that method, you can fill it to any level without wasting tons of CO2 in after purging, while everything remains oxygen free, or pretty much.