Lower RIS FG by racking to lager yeast cake?

I have an AG Imperial Stout that has reached terminal gravity at 1.040 down from 1.115 I know it's finished because I've roused it, warmed it, and its been over a month in primary, plus my forced fermentation test finished at the same FG. Malt bill had a lot of caramels (14%) and roasted (14%) grains + high mash temp (69*c/ 156*f) seems to have left slightly too many unfermentables. Yeast is WLP007, I calculate the attenuation at 68% for 10% ABV so its not far off the bottom range of 70-80% published rates.

Anyway, I'd prefer it down to the planned 1.030 if possible, so my question is... Is it worth racking to a fresh W-3470 cake? I am I correct in thinking the lager yeast is capable of eating up some of the sugars the ale yeast has left? Is it worth a shot?

Cheers

 

Thanks for the quick replies guys.
I don’t think i’ll bother if you’re not sure it will work - another chance to oxidise between transfers. I’ve got a bit of a sweet tooth and the 90 IBU’s of Columbus should provide some balance. I’ve read some comerical brews (bourbon county) finish up in the 1.040’s too.

@GormBrewhouse I’ve seen @stealth’s ‘none blacker’ Stout Incredible! I’ve got one planned myself but on a smaller scale, hoping to take 001 upto 15%. I’ve read 099 become wine like above 16% which is something I’d want to stay clear of.

 

Thanks for that, I like the idea of getting the funk to where you want it and then killing it off as to not over-power. I have a bottle of De Dolle Export Stout I could even culture from. Also useful if it gets stuck high I could use Brett to lower.

 

I last sampled at the weekend. It tastes pretty good, I wouldn’t actually describe it as over sweet. It’s a 6.5gal batch with roughly 1lb of chocolate, 1lb of pale chocolate and 1.5lbs of roast barley. Main flavours are heavy roast, lots of coffee and a bit of dark chocolate.

Ive made an imperial milk stout in the past with WLP005 that finished at 1.048, at first I thought it was incredible. Everyone that came over thought it was like chocolate milkshake, but they only drank small pours. I got bored of it quickly, it was a chore to get through. I ended up bottling loads off the tap and giving it away. That’s why I wanted this one to finish drier and roastier, but equally I’m not sure I want to throw Brett at it or anything too funky yet. The only wild stout I’ve had so far is Cantillon Zwanze 2015, and I didn’t really like it! I don’t have a local shop I can run to, I have to order everything online and the flat shipping on one yeast is cost prohibitive, I don’t need any other supplies either as I’ve just had everything delivered for my next stout with WLP001 (which I plan to mash lower!)

Anyway thanks for help/ suggestions so far. I’ll probably rack it to a keg and start drinking, but could I possibly pitch a higher attenuating yeast in a month or so if I do get bored?

I’ve not moved the lager just yet so that’s still an option, but I understand from above responses that the yeast in the cake may not be any better at fermenting the types of sugar left in my beer.

 

Thanks for that breakdown. I don't think the 007 crapped out as I've taken it higher before, but from what you say most likely not worth the risk of an additional transfer.

What i'm going to do is leave most of it untouched, lesson learnt - mash lower and longer with less crystal or more sugar next time.

1.25 gallons I'm going to rack to a small carboy and see about inoculating with a wild strain I will cultivate from a bottle. Am I right in thinking I should leave very little headspace as there shoudn't be much krausen?

Cheers

 

Ah of course. I was forgetting I’m basically at the SG of a session beer.
I was thinking Orval. I like it, fresh bottles are cheap/ easy to find, young it’s not over the top funky and it’s low enough ABV% to be still have good viability.

 

Update:

I couldn’t be bothered to cultivate from a commercial bottle in the end. What I did instead is pitch a re-hydrated packet of Lallemand Belle Saison from a local shop (which I belelive to be the dried version of 3711) It dropped the gravity down to 1.031 (additional 9 points)

I’ve had the other 5 gals of 1.040 FG on tap for over a month now. Honestly, there’s not much in it. The 1.031 feels slightly drier/ a touch less thinner in body as expected, but the extra ABV% isn’t perceptible, there’s no real difference in flavour/ sweetness, no saison yeast qualities come through.

Ultimately, both are very good. I wont sweat it in the future, I’ll pay closer attention to mash temps and let them finish where they finish.