Stuck Fermentation on a High Grav RIS

[Daparish]

Looking for some insight here. I brewed a partial mash RIS about 5 weeks ago. SG of 1.120 and I pitched it on a cake of White Labs California V ale yeast from a blonde ale that I had brewed earlier in the month. The ale yeast crapped out when the alcohol got too high (around 1.055). I added a packet of dry wine yeast and I have been rousing the yeast every two days for the past two weeks. My RIS is only down to 1.035-1.037 and holding steady, even after I raised fermentation temps to around 75F. I've tasted it and it is still too sweet to taste the roastyness of the malts like a true RIS.

Any thoughts on how I can bring it down another .010 or so?

 

[PorterIV]

From looking at White Labs website it looks like California V is rated as "Medium-High" alcohol tolerance. With that high of a SG it must have just been too much.

You might try Super High Gravity yeast WLP099 - I have never used it but it should get you up to at least 80% attenuation. A slightly different idea my be to drop the temp and try the Zurich lager yeast WLP885 which is what people use to clone Samiclaus.

 

[BrookdaleBrew]

I don't think more yeast is the answer at this point. A RIS is going to finish high. I'd call it done, bottle/keg and let it age for 6 months. You may be surprised how it changes.

 

[Daparish]

I don't think more yeast is the answer at this point. A RIS is going to finish high. I'd call it done, bottle/keg and let it age for 6 months. You may be surprised how it changes.

I'm just worried that it's not balanced at this point. It still tastes cloyingly sweet. I'm also going to bottle this so I can age it for a few more months, and I'm worried that when I introduce fresh yeast, I may be setting myself up for bottle bombs. At the minimum, I don't want to open a bottle in six months only to find that I still have black syrup that's hard to get down.

Does anyone have experience with a brew this big? Around 12% ABV?

 

[JLem]

I've never done anything quite that big. My biggest, a barley wine, topped out at 1.100 or so. Using regular ale yeast I got it down to 1.022-1.025 range.

Given your FG, I wouldn't expect to get below 1.030, so you are probably as far as you are going to go. Especially if you used a fair amount of extract. Also, how much grain did you mash and at what temp?

 

[Daparish]

I've never done anything quite that big. My biggest, a barley wine, topped out at 1.100 or so. Using regular ale yeast I got it down to 1.022-1.025 range.

Given your FG, I wouldn't expect to get below 1.030, so you are probably as far as you are going to go. Especially if you used a fair amount of extract. Also, how much grain did you mash and at what temp?

This batch was 15 lbs of LME and only maybe 3 lbs of grain mashed at 154. In hindsight, I should've used a more attenuative yeast with a higher alcohol tolerance. The California V is a weird yeast for an RIS, but I had a whole cake of it.

 

[JLem]

with 15 lbs of LME, I think you are done. I don't think it would have mattered if you used a more attenuative yeast either. The yeast can only eat up the fermentable sugars you have and with that much LME, you are going to have a bunch of residual non-fermentables. The fact that the pitch of wine yeast only got you to where you are is more proof that this is as far as you can go.

And for future reference, I would probably mash lower with a beer this big - you want as much help to dry it out. I'd go 150 or even lower.

 

[Daparish]

Would adding Beano or amylase do anything?

 

[JLem]

Would adding Beano or amylase do anything?

perhaps - both will take complex carbs and convert them to simple sugars that the yeast could then ferment. However, I've never used either and have no idea if there are caveats to using them.

 

[tlael]

I don't think more yeast is the answer at this point. A RIS is going to finish high. I'd call it done, bottle/keg and let it age for 6 months. You may be surprised how it changes.

+1 The numbers you gave indicate 70% attenuation, which is on the low end for this strain, but believable.
Let 'er sit for a couple months and the sweet may balance out into some more malty character.

 

[Daparish]

Thanks for the info guys. I'll let the board know how this one turns out in a few months.

 

[SwampassJ]

Would adding Beano or amylase do anything?

You can try Amylase but do not do it with beano. Beano is a runaway that won't stop until the beer is as close to water in weight as possible. I used it in a cream ale and it took 6 weeks to finally finish.