Formaldehyde Pumpkin ale

[Nike_Eayrs]

So I brewed my first ever pumpkin ale. After 3 weeks in the fermentor, I kegged it. I let it force carb and poured a pint over the weekend. It tasted awful! I've never drank formaldehyde, but I can't believe this is too far off. I guess I am looking at any ideas as to why this happened. This is the first time I've ever run into an issue this severe, it's all going down the drain. It smelt kind of funky when I was transferring, but I thought maybe it was the Co2/pumpkin mixture. I've posted the recipe below, and appreciate any help. Lastly, this is the first time I used dry yeast, could that be the culprit?

12lbs 2-row
.5lbs 60L
.5lbs biscuit
.6oz magnum at 60 min
2 big cans of pumpkin puree at flameout
safale US-05 after wort was cooled to 65 degrees
2 tsp's of pumpkin spice and 4 tbs of pumpkin extract at kegging
3 weeks primary, 2 weeks on the gas

 

[atom]

i used us-05 in my pumpkin ale and it's delicious, so you can rule that out...

i've always mashed pumpkin...never added at flameout...seems like an awful lot of pumpkin spice.

 

[prohl84]

US 05 is my normal yeast and I have never had aroma or flavor I would call formaldehyde. How much did your big cans of puree weigh and did you roast it? Pumpkin in large amounts can get weird- if I had to blame anything in your recipe though it would be the extract. But I cannot say for sure since I have never used it- I have tasted some pretty nasty extracts though. The weird pumpkin assertiveness does mellow over time- from fermenter to bottles my first pumpkin beer smelled like rotten melons which didn't completely go away until about a month in bottle. After that it was delicious and subtle- more like the melon and less like the rot.

Did you happen to change anything in you sanitation method like using tap water instead of RO for cleaners?

I too use pumpkin in the mash.... that may be your problem all that trub- or did you get rid of most of the trub?

 

[jrgtr42]

What was the mash and fermentation temperatures?

 

[Nike_Eayrs]

I mashed it at 164 and it fermented in a room that has an ambient temp of 65 degrees max. I brewed an IPA the same day, and fermented in the same place that turned out amazing.

As for the trub, it wasn't bad at all. I ended up with a little over 6 gallons and kegged roughly 4.5 to avoid the issues. The crazy thing is there is NO pumpkin smell or taste at all. I honestly gagged when I took a little sip, and it smelled really funky.

 

[brick]

I mashed it at 164

You mean 154?

 

[Nike_Eayrs]

I was wrong all the way around. I looked back at my notes and the mash temp was 159. I was trying to get some sweetness out of it. Nice catch!

 

[GuldTuborg]

Pumpkin extract? Ugh, that can't be good. If that pureed pumpkin made it into the fermentor, as well, it's possible that caused some problems. Really, I'm just guessing, though, as I have never used these ingredients or techniques.

 

[Nike_Eayrs]

The extract actually tastes pretty darn good. I tried it in some light beer and it gives a really nice pumpkin flavor. I've ruled the extract out, as the beer had the dreadful smell before I ever put it in the keg (which was when the extract went in). Is this jsut a simple infection? I've never brewed a beer that had one, so I don't have anything to really compare it too.

 

[GuldTuborg]

Well, perhaps I'm wrong on that judgement. Infections come in all shapes and sizes, so it could be that. Usually, you'll see a lower than expected gravity, if that's the case, but not always.

 

[BDsnakey]

Hey,

Funny you mentioned this because my Smoked Pumpkin Saison that I bottled yesterday, I have a feeling, will be the same way. After a OG of 1.083 the final was 1.009... which turns out to be 9.5%ish minus temp corrections...first that was a little too much. my mash temps were not controlled very well because i was using a kettle burner combo, and not a insulated container to hold the temp. this resulted in mash temps fluctuated on the high end. there was plenty of sugar that should have left plenty of sweetness but I left the primary and secondary sit an extra 2 weeks... so now when I taste it hardly has any sweet flavor, the smoked pumpkin chunks you can only taste on the back end after, you wipe the grimace off of your face from the sharp/cardboardy alcohol flavor. The last kicker the best storage place I have right now is on the dining room table... next to a window... wondering if the light was also doing something to it. All in all, I think it was a failure and I have a feeling it will be like " Samuel L. Jackson.... IT GETS YOU DRUNK"

 

[Darwin18]

http://www.bjcp.org/faults.php

This is where I would start. You're describing an off-flavor and aroma that might be a combination of factors. The formaldehyde flavor that you're describing sounds like it would be solvent-like, perhaps like nail polish? That to me, just shouts "High Fermentation Temperatures". I know you said you're fermenting in a room that has an ambient max of 65F, but how exactly are you measuring that? Is that the average for the entire day? The room, if it's like any normal room in a home, will experience temperature shifts throughout a 24 hour period.

 

[Nike_Eayrs]

Thank you Darwin18, that was one of my thoughts too. The main point behind asking was in regards to US-05 as much as anything. I've fermented with Wyeast 1056 in the same room with even warmer temps and there has never been an issue. The batch right beside it was fermented with San Diego Super Strain, and it tastes great. It ferments in a shower stall of an extra bathroom that is seldomly used and the door is kept shut a great majority of the time (the wife is real thrilled about it). I guess my question is, are dry yeast strains more delicate than liquid?

 

[prohl84]

I do not know enough about liquid yeast to draw any real comparison; I have had so much success w/ dry yeasts- particularly US 05- it's hard to justify the extra expense. Regarding their resilience I am fairly sure they are more stable than liquid yeast- you can freeze them as long as they are sealed. US 05 has always performed well for me < 70*F clean tasting beers from Blondes to Imperial Stouts and everything in between. I practically flew through the pumpkin ale that I just made w/ it beginning of October.

edit: it was actually a golden hubbard squash I roasted- which is often what canned pumpkin actually is if I am not mistaken. I have also had great success with butternut- a tad fruitier; hubbard is earthier and has that classic pumpkin flavor.