dry out high gravity beer, go further 10% ABV

[piteko]

Hi,
I made an imperial stout that started at 1110 and now it's at 1032. The yeast I fermented it with is wyeast 1728, which should tolerate 12% ABV. I used it for a 70/ then repitched to get a good pitching rate.

At this point it's at 10.4% ABV so I think that the yeast has done a good job, but I tasted it and I think it would be better if it was dryier. The wyeast 1728 alcohol tolerance is beyond that, so I suppose that the yeast is not able to eat any more and I should concentrate on switching to a yeast that is more attenuative than this.

I purchased today a package of Danstar CBC-1 (which has a great alcohol tolerance but I don't know how much attenuative is) and I can collect some Danstar Belle Saison yeast from some bottles of a wit I made 2 months ago. My first choice would be to go with the Belle Saison, which I know to be an extreme attenuator and on the Danstar site is described to have a high alcohol tolerance. Note: I'm dealing with 5 liters here (1.25 gallon) so I don't need to make extreme starters etc...

So, what's your opinion?
Cheers from Italy
Piteko

 

[catdaddy66]

I just bought some Belle Saison yeast because I want to make my first "big" beer. I've not used it but also read it is good in a high alcohol environment. It is supposedly a great attenuating strain also and can bring the gravity to or below .010.

That's what I would try 1st, but that's just me! Good luck!


Sent from my iPhone using Home Brew

 

[flars]

I have never added yeast to a wort that is near finished with a high alcohol content. With my limited knowledge will the fresh yeast be able to perform in a high alcohol environment. The alcohol content may cause ruptures of cell walls due to osmotic pressure before the yeast can begin budding.
Could it be better to make a small starter to acclimate the yeast to an environment with alcohol and pitch at high krausen?

 

[jnacey]

Couple of questions/observations:

1) How long has it been fermenting? Is gravity stable?
2) How much slurry did you pitch?
3) It's hard to tell where this should end up without seeing your recipe.
4) What was the estimated FG on the recipe?
5) What temp did you mash at?

Those items aside, I'd recommend giving the carboy a slight shake to rouse up some yeast if you're worried it dropped out too early. A lot of the great examples of RIS/Imperial Porters finish quite high, some higher than what you indicated. As always, taste is very subjective, but if this is where your recipe was supposed to finish, you might be surprised how this tastes after getting some age on it.

 

[peterj]

I think adding Belle Saison will dry it out more than you want. That yeast will take wort into the 1.000 range. While I don't think it will bring your RIS down that far, I think it will go farther than you want. That is if it can even get started in such a high alcohol environment like flars said.

I think you're going to be fine at 1.032. That's pretty much on target for a RIS. It will taste A LOT different when it is carbed and cold. I thought the same thing with a RIS that I bottled about 6 months ago. It finished at 1.032 and I thought it needed to be drier when I tasted it out of the fermentor. I just went ahead and bottled it and I'm glad I did because it turned out great after it was carbonated. Much drier seeming than straight from the fermentor.

 

[piteko]

1) How long has it been fermenting? Is gravity stable?

mashed 9 march, krausen after 36 hours, was at 1040 on 15 march, ramped up a bit on fermentation temp and let it sit for a month. When was stable at 1032, splitted in half. Gave some chips to the first half, let it sit in the fridge and then bottled. The other half is waiting for me.

2) How much slurry did you pitch?

Given harvest date, mr malty called for 130ml, I pitched 170ml (I'm talking about 10 liters, about 2,5 gallons because I parti-gyled making a mild too).

3) It's hard to tell where this should end up without seeing your recipe.

81% maris otter
10% of different roasted malts
4% of carapils (I had some problems with foam on the last run)
5% crystal 80L

the 1728 finished with a 71% of attenuation which is perfect for the 69-73% range given on the site.

4) What was the estimated FG on the recipe?

didn't have an estimate. my usual OG was around 1094 but I had some problems with the boil so this time was much more extended and it landed me at 1110. The last round FG was too high so I changed the mash temp too.

5) What temp did you mash at?

30 minutes at 62°C (144°F)
50 minutes at 65°C (149°F)
mash pH 5,25

As always, taste is very subjective, but if this is where your recipe was supposed to finish, you might be surprised how this tastes after getting some age on it.

I agree, that's why I bottled anyway half of the batch. I took some fresh 1728 yeast (from the mild), made it krausen with some sugar and bottled with it, I hope it's carbonating properly since alcohol tolerance shouldn't be an issue. I usually make this recipe one year for the other but I usually take a sample at 6 and 9 months too

Cheers from Italy!
Piteko

 

[piteko]

Could it be better to make a small starter to acclimate the yeast to an environment with alcohol and pitch at high krausen?

Indeed. I was thinking at making a small starter and, at high krausen, adding small amounts of beer to the starter (and not, as usual, vice versa) to raise the alcohol volume slowly.

Cheers from Italy,
Piteko