High gravity pumpkin ale question

[johnnysoj]

Hi there,
I have a 3 gallon BIAB pumpkin ale (NB Smashing Pumpkin scaled down to 3 gallon w/ a little more 2 row base malt, and a can of libby's pumpkin) in the secondary for about a week now. my FG is ~1.029. Seems very high to me.

I think I may have had some issues with fermentation temperature being too low (~55f Safale US-05), so I thought my yeast were shot. I pitched about 1/2 cup of a starter back in after I corrected my fermentation temperature, and let it sit for a few days, but the gravity hasn't gone down any.

The beer tastes pretty good, albeit a little sweet.
I would like to bottle, but I'm afraid there may be some bottle explosions if I do.

I'm sure my options are limited, but any suggestions about what I should do with this? If I do bottle, they'll be stored in a milk crate, and the milk crate will be sitting inside a plastic box to contain any potential shrapnel and liquid nastiness.


John.

[GilesTH]

Hi there,
I have a 3 gallon BIAB pumpkin ale (NB Smashing Pumpkin scaled down to 3 gallon w/ a little more 2 row base malt, and a can of libby's pumpkin) in the secondary for about a week now. my FG is ~1.029. Seems very high to me.

I think I may have had some issues with fermentation temperature being too low (~55f Safale US-05), so I thought my yeast were shot. I pitched about 1/2 cup of a starter back in after I corrected my fermentation temperature, and let it sit for a few days, but the gravity hasn't gone down any.

The beer tastes pretty good, albeit a little sweet.
I would like to bottle, but I'm afraid there may be some bottle explosions if I do.

I'm sure my options are limited, but any suggestions about what I should do with this? If I do bottle, they'll be stored in a milk crate, and the milk crate will be sitting inside a plastic box to contain any potential shrapnel and liquid nastiness.


John.

What was your OG and mash temp?

[johnnysoj]

OG was 1.062 w/ a mash at ~154 give or take a degree, no mash out or sparge.

[GilesTH]

OG was 1.062 w/ a mash at ~154 give or take a degree, no mash out or sparge.

Hmm... you might've just gotten a stalled fermentation. 154 should've gotten a higher degree of fermentable sugars, but with dry yeast at such low temps, the viability to begin with (with or without a starter) might not have been up to par for the conditions.

What's your temp at now?

[Ozwald]

First off, I definitely wouldn't bottle yet.

This just happened to my buddy's first brew, although his was the NB Caribou Slobber kit done straight up. I'm bummed because I thought I had the deck stacked in his favor & his first batch would be a home run. In his case, I'm 99% sure it was the dry English yeast that came with the kit & an unexpected warm up a day or two into the ferment. I recommended nutrient & a clean secondary strain for his.

That's mostly applicable for your beer, but you're definitely having a different yeast issue. If US-05 behaves like it's very close cousin 001, it is possible to get a great ferment at 55F, but it requires quite a bit of yeast conditioning & it definitely won't go straight out of the package.

Did you calibrate your hydrometer recently & did you double check the hydro sample temp. Sorry if you have, but those are often overlooked.

Was this a single step mash @ 154? If so I'd be curious about how the added pumpkin handled the conversion. I don't think it's really the big factor in the high FG issue but it might be playing a part.

Depending on what you're at now, I would warm it up to 68-74F, frequently swirl the lazy bastards back into solution, add some good nutrient slurry made with pre-boiled water & be absolutely sure you're wearing clean at every step of the process.

[johnnysoj]

This was a single step biab mash.
the canned pumpkin was added the last 15 minutes of the mash. This was more of carelessness on my part rather than any technical reason. My hydrometer works well. And the beer is currently sitting at 70 degrees and has been at this temp for about six days now.

would it make sense to add some more fermentables and yeast to this?

[Ozwald]

More sugars won't help at all. Yeast, perhaps but I'm not thinking so (it may be worth a try - definitely better than dumping the batch). Without having converted the pumpkin, you may be out of luck. Sorry I can't offer more insight, but on my list pumpkin beers rate a half a step above Oktoberfests... which are both way below PBR & BMC.

[Afterlab]

...a mash at ~154 give or take a degree, no mash out or sparge.

Here lies your problem. Even if you hadn't used pumpkins in the mash, not raising the temp up to 168-170 for mashout and sparging is not a very good idea. Especially for long term flavor stability. 154 was a fine temp for saccharification but not nearly warm enough to ensure all the wort components were fully dissolved into a low viscosity wort. I'm going to go out on a limb and assume your pre-boil and potentially your post-boil wort was fairly hazy and starchy? If that was the case then you likely had a LOT of long chain carbohydrates, starches, lipids, proteins and other unfermentable compounds from the pumpkin (not the mention the grains), that are simply too large and/or unappealing for the yeast to break down. You could have the healthiest and biggest pitch of the most attenuative ale yeast available and they are not going for those overly-complex carbs. Next time I would suggest including the pumpkin for the entire mash and using a Protein Rest, extended Beta Rest and Alpha Rest and a Mashout.