Overpitch Diacetyl

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ChaosB

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Think I might have overpitched my last batch which is now riddled with a flavor I believe to be diacetyl.

Made a 2 L starter with WLP001 dated best by 17 MAY 20 around 15 MAR and used a stir plate. Didn't get as much yeast at the bottom of my flask as I normally see and didn't end up brewing the day I wanted to and left the starter at 37 F for about a week so was concerned I would be underpitching into this 10% recipe. Decided to pour 2 packets of US-05 unrehydrated into the 5 gallon batch as well.

Fermentation made the most krausen I've ever seen. Kept at 68 F and raised to 69 F for the last 2 days. Seemed to finish in about 7 days. Added my dry hops for another 3 days then cold crashed with gelatin for 2. Kegged and carbed using carb stone lid for a day.

Maybe I didn't leave the wort on the cake long enough before cold crashing. It is indeed 10.5% and reached FG, maybe the yeast didn't finish clean up.

Maybe yeast were stressed and didn't finish life cycle due to overpitching?

Detecting a taste that I noticed a bit on my last batch but much stronger now, pretty much undrinkable. Thought it was kind of cheesy but maybe it's buttery, I don't know. Used Coastal Haze Ale yeast on the last batch which was a NEIPA and I think the esters covered it up better than the neutral chico yeast now with this west coast DIPA. On last batch, had suspected it was due to oxygenation as it got worse with age.

Considering I thought it was more cheesy than buttery, I thought about my hop storage but I'm using 2019 crop from Yakima Valley, stored in vac packs in the freezer. I wouldn't say the mouthfeel is slick.

I cleaned and sanitized my keg and beer lines between batches. The fermentation vessel was a plastic PET carboy. Not sure if it's the same one I used for the last batch as I have multiple. Not sure I want to replace that. Definitely will replace the blow off tubing I know was used on both batches.

Always thought an infection would look obvious if that was the problem. Maybe not. Seems like I have enough contributing factors that I could blame yeast health but unsure at this point since I noticed it last batch to a lesser extent as well.

Keg is currently warming to room temp and considering making a 1 L starter of Wyeast 1056 to add to keg at high krausen and hope the yeast cleans it all up.
 
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1 L starter finished and started dropping out a lot faster than I anticipated, less than 24 hours on the stir plate. I may have missed my high krausen window and I don't know if it's going to be effective in cleaning up what I suspect is this diacetyl flavor but pitched it into the keg anyway.

Forgot to mention, I also pulled some with a picnic tap and tasted the same so that should rule out the kegerator lines.

Also broke my regulator when changing out lines to re-pressurize the keg. The brass shut off valve just split in half, so that's nice.
 
Maybe I didn't leave the wort on the cake long enough before cold crashing. It is indeed 10.5% and reached FG, maybe the yeast didn't finish clean up.

With that big of a beer it is likely that it hadn't finished cleaning up diacetyl but all is not lost. The keg still has plenty of yeast for the cleanup so....I'd rock the keg around a bit to re-suspend as much yeast as I could and warm it up to the low 70's for 5 to 10 days before chilling it again. Good luck but I think it will clean up.
 
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