correcting a high finishing gravity

Some club members brewed about 50 gallons of Russian Imperial Stout, several batches of the same recipe averaging an OG of 1.105, and filled a bourbon barrel with it last July.  We divided it up a week or so ago after 7 months.  The final gravity was high when it went in at 1.030, but I figured time and wood would dry it out.  It didn’t.  It’s still 1.030 and much too syrupy to be enjoyable even after force carbonating my portion.
I’m thinking of adding a diastaticus strain like 3711 or maybe some enzymes or possibly some brett.
What would you guys suggest?

I think I’d go the blending route rather than add something that would alter the character of the beer like 3711.

I’m not sure of adding 3711 would work, but I agree that I don’t think that I’d like it in a stout. I’ve had a couple of Brett stouts that were enjoyable, but I don’t know if I’d want 5 gallons worth.

Maybe cut it with some whiskey and let it age a bit?

At 9.84%, I suspect that the culture gave out from having to deal with high osmotic pressure followed by high ABV.  I posted this information several years ago, but K1-V1116 is an RIS problem solver.  Unlike most wine strains, K1-V1116 can ferment maltotriose and is good to 18%. You are going to need around 200 grams for that much beer and I would rehydrate it as insurance against premature cell death.  If high osmotic pressure followed by high ABV weakened and then killed of the yeast culture, K1-V1116 should bring the final gravity down by at least a few points.  Beers that big are not conducive to using just one yeast culture, especially if the culture is an ale culture.

I’d consider split batch and attack from various angles, including Brett.  But there are likely some yeasts that could be used via a starter at high krausen (so using just that approach would be a blending and re-yeasting, i guess).

I would make the same recipe and blend it back to preference.

My portion is less than 5 gallons.  Would 200 grams be the dosage for 50?

I have some 2.5 gallon kegs, so I may split it and experiment.  The Brett seems intriguing.

You only need 20g for 5 gallons

I had a Dark Belgian Strong that stalled out at 1.033 and wouldn’t budge no matter how much active yeast I pumped in (and I pumped a lot it 3 different times). Finally I dumbed a few bricks of Belle Saison in and it dropped it around 1.010. Which was then too dry and would probably be way too dry for your RIS.

Interesting. I’ve never considered 3711/Belle as an option to finish a stalled fermentation, but it makes sense since it is a diastaticus strain. Did you notice any other flavor impact besides drying out the beer?

If it were me I would try the K1-V1116. It should bring it down quite a bit without adding a different flavor.

The beer tasted great! There was a bit of a peppery finish that wasn’t there before but not overwhelming and blended well with what residual sweetness there was. Bottom line, it saved a beer that was going to be salvaged in the still or dumped. The only problem was since it was diastaticus it couldn’t go through the canning line and the ABV no longer matched the label.

same, i tried adding a diastaticus strain to a sorta high alcohol beer that finished high and it didn’t change the fg by much at all, about 0.002 or so

It’s a dumper, just gonna have to rebrew it.

What about adding some gypsum to a sample and see if that is enough to change the perception of the beer and mouthfeel.