RIS - Should I mash low?

[BrookdaleBrew]

I'm brewing a RIS on New Years Day with an expected OG of 1.120. The grist is about 75% base malt and 25% specialty malt. Ideally I'd like to see an FG of 1.020-1.024.

I'm thinking if I mash around 150 for 90 minutes, I'll get a pretty fermentable wort even with all the specialty malt. My question is, is that too low for that high of an FG? Obviously I don't want it to go too low but I'm thinking with that much specialty malt, it'll be pretty much impossible.

Planning on pitching 2 packets of US-04.

 

[BeernuT100]

149 - 150 is fine. This where I would want mine to be.

 

[BeernuT100]

Although I do not believe S-04 is going to get you down that far.

That comes out to be about 13%, I think you will find S-04 will get you close to 8% tops on a good day.

 

[BrookdaleBrew]

Thanks for the suggestions. I've heard of people getting 80% attenuation with S-04, so we'll see. I think if I aerate well and pitch the yeast rehydrated, I have a pretty good chance. I won't be devastated if it finishes a little higher though.

 

[BrookdaleBrew]

That comes out to be about 13%, I think you will find S-04 will get you close to 8% tops on a good day.

Hmm, I was under the impression that S-04 was the same strain as WLP007, which supposedy maxes out around 12%. I don't have much experience with that yeast though. I was thinking I could squeeze out another 1% if I pitched enough active, healthy yeast. Maybe I'll just go with S-05 since I know that'll get the job done.

 

[OLDBREW]

pitch 3 pks with a lot of froth beaten into the wort. even though they say aeration isn't needed in their yeast when re-hydrated I don't think some extra O2 will hurt!

 

[BrookdaleBrew]

I may just do 3 packs of rehydrated S-04 and see what happens. If it finishes really high then I'll pitch a few packs of rehydrated S-05 to hopefully get it down a little more. That way I get some of the yeast character of the 04 and the attenuation of the 05.

I really want this beer to turn out though. The plan is to bottle in corked champagne bottles and crack the first one open at midnight on January 1st, 2012. Then I was going to crack a few more every New Years Day for the next 5 years or so.

 

[BeernuT100]

Hmm, I was under the impression that S-04 was the same strain as WLP007, which supposedy maxes out around 12%. I don't have much experience with that yeast though. I was thinking I could squeeze out another 1% if I pitched enough active, healthy yeast. Maybe I'll just go with S-05 since I know that'll get the job done.

S-05 may get you closer and be a better choice over S-04. Let us know how it goes.

 

[SpanishCastleAle]

FWIW, I recently brewed a RIS with a washed slurry of S-04 but my OG was only 1.092. The fast ferment test finished at 1.021, main batch is still fermenting. I didn't mash low or extremely high, IIRC it was 153* or 154* F but my beers almost always attenuate on the high side for a given mash temp.

 

[BrookdaleBrew]

Thanks for the info, that is definitely helpful. Another thing I have to consider is that I'm basing the predicted OG on my normal efficiency of ~75%, but I'm thinking it'll likely be lower since I'm mashing 25lbs of grain.

 

[SpanishCastleAle]

That will depend on your system but most 5 gal batch brewers would have lower efficiency with that much grain, I know I do. When I brewed that RIS I decided that in the future I was going to use a full 3# bag of DME in these really big beers and use 5# less base malt (partial extract?). Which is still a lot of malt but that 5# difference makes it quite a bit more manageable and I get more consistent efficiency/OG.

 

[smokinghole]

I got a batch of DIPA to 9.7% with So4. Now with that said I would go with a higher alcohol tolerant yeast like WLP001, 028, or 099. I mashed my RIS at 149 but got stuck at 1.040 and I am waiting on brewing a beer up with 099 to get it to finish out.

 

[kanzimonson]

I think of S04 as between 002 and 007. I've found 70-75% attenuation to be my expected amount, but I haven't used S04 more than a few times. When I use English ale yeasts in big beers, I almost always have a sugar addition - at least 5% and sometimes as much as 15%.

I wanted to add a comment to the plan of mashing low: whenever I make a beer where I want a lot of attenuation, I'll mash at 148-150 for an hour, and then raise the temp to about 153 for another 30 minutes. I started doing this after reading about gelatinization temps of starches. I didn't do a whole lot of research afterwards but just started implementing it and haven't changed since. Someone with a little more knowledge might be able to expand on this.

 

[BeernuT100]

I think of S04 as between 002 and 007. I've found 70-75% attenuation to be my expected amount, but I haven't used S04 more than a few times. When I use English ale yeasts in big beers, I almost always have a sugar addition - at least 5% and sometimes as much as 15%.

I wanted to add a comment to the plan of mashing low: whenever I make a beer where I want a lot of attenuation, I'll mash at 148-150 for an hour, and then raise the temp to about 153 for another 30 minutes. I started doing this after reading about gelatinization temps of starches. I didn't do a whole lot of research afterwards but just started implementing it and haven't changed since. Someone with a little more knowledge might be able to expand on this.

That's probably a good way to look at it, but realize that it isn't a question of attenuation so much as it is a question on the alcohol content in the beer and the ability for the yeast to survive long enough to finish it out.

-bn