Kit + hops brew turned into buttery monster - can I fix it?

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Swannie

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Hello all,

After an almost 3 year break I've got back into brewing. I had three brews, that progressively got worse, so I decided to "start again" with a new fermenter - a fermzilla all rounder, and make sure it was one that could fit in my beer fridge for controlled fermentation. All was going well... except now I get a big hit of butterscotch - the big D. I think I know why... but what should I do about it?

Process:
I put down a Coopers "Brew A" IPA, with 1k DME, in ~21 liters. I took the DME and tin up to about 80ºc, and added 10g cascade as a "whirlpool" addition. Pitched (edit: dry, a packet of US-05) a little on the warm side at about 26ºc, but straight into the fermenting fridge. It was down to my target fermentation temperature of ~17c after maybe ~6 hours. A bit slow to start (I suspect I didn't aerate well enough, as I didn't get much foam on top), eventually a solid fermentation over many days. After a week, I upped the temperature a degree a day to ~20.5, and kept it there until it was 2 weeks since brew day. Day 12 and 13 I had equal gravity readings that matched expected attenuation. I cold crashed down to ~6.5ºc (beer fridge didn't want to go lower until I turned the freezer compartment right down too...doh). Then I dry hopped 40g of cascade pellets. I had been reading about cool dry hopping being just as good, if not better, than during active fermention to get more aroma, and not needing too long, so my dry hop was 36hrs. I closed transferred to a santised keg after ~15.5 days.

At this point, the beer tasted good, but green - fair enough. It had potential to be my best beer yet. I was cautiously optimistic. Next few days I tasted, and yes, the body developed, the green hops subsided, bitterness rounded out... it was going well! After a week in the keg, it was noticeably sweeter, with good hop aroma. I came back 2 days later... and BAM, butterscotch popcorn, as soon as I started pouring. Still some hop aroma, but totally drowned out. No longer a well rounded beer, the aroma of diacetyl just dominated.

At this point I am thinking many things:

- Maybe I missed this during my initial testing? But surely a few days at 20.5 would have been enough of a d-rest? Maybe I needed to be a bit more patient?

- Could this be from excessive oxygenation late in the process? I had been careful to purge my keg - the only time O2 would have been added was during my quick dry-hop, which was fast, < 3mins, through a port, not removing the whole lid. And I'm not picking up any other wet cardboard type flavours - though now the beer is a month old, I'm getting slight hint of stale beer aroma. So maybe that bit of O2 allowed the diacetyl precursor to convert? Maybe this late dry-hopping business only really works well if you can do purged hop additions? Going to invest in some magnets to do future additions without opening.

- Could this be from "hop creep" - the hop enzymes to have made some fermentable sugars, and there was enough heat and yeast activity to produce diacetyl precursors, but not enough to clean them up?

- Maybe this is an infection? Pediococcus? I'm not picking up any sour notes though.

So a few things to try and improve on during the process. But I'm trying to figure out - which one of these is the most likely? I'm leaning towards it needing a longer d-rest, and not noticing during samples because I cooled them down to settle the yeast before tasting.

But if it is hop creep - could taking the keg out of the fridge and letting it warm up to ~18ºc in the garage for a few days help reactivate the yeast to clean up?

I am thinking I will fill a couple of bottles, as best of a closed transfer as I can (I have carb caps and a t-peice, should be able to rig something up), and see if conditioning them at 18ºc for a few days improves things.

Any other recommendations? I was wondering if more sugar would help rouse the yeast and encourage clean up. Or if more dry hops could help mask the flavour (I think it's likely to cause more oxidation than its worth though). Or maybe just leave it another month?!

Cheers!
 
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Droopy Brew

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Diacetyl should have been noticable straight away. The fact you got sweetness and butterscotch a week after kegging sounds like oxygen to me.
Did the beer change colour? Did it turn a murky brown at the same time? If yes then oxygen is your culprit. I doubt hop creep would be a factor with only a 40g addition.

If it is O2 then there is no fix sorry.
 

Swannie

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Hmm, if it's O2 then I guess I'd better keep drinking it before it turns to wet cardboard!

I'd guess then on my first beer that I also dry hopped, and with hindsight, it probably did have just perceptible levels of diacetyl, but I left the beer on the hops and yeast for a lot longer than 36hrs, giving the yeast time to metabolise more of the O2, and then bottle carb'ed, further giving the yeast time to clean up.

I'm not super big on noticing beer colour... I don't think it has got darker, and still nice and clear.
 

MHB

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I'll take a different stab - Sounds like it could be your lines are infected.
With a new fermenter and the way the problem is getting worse in the keg (unlikely to be the keg) I would replace the line and give everything else a down to parts clean and sterilise.
Mark
 

Swannie

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Why are you heating the extract, its an unnecessary step .

The tin? Honestly, I don't know. Now you point that out, it makes no sense. The was DME was for hop extraction. I was going to do a short boil, but ran out of time...

I was rushing to get the brew in the fermenter early Sunday morning before SWMBO wanted me out the house.
 

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