[jlap]

I'm looking for some tips on how to reduce the alcohol character of big beers.  I'm scoring in the 36-39 range with my big beers (A. Barleywine and RIS specifically) but I perceive, and I'm getting comments back, that the alcohol is too obvious.  I've been doing this beers with large stirred starters via Mr. Malty Calc - usually 4-5 L with one pack of yeast.  I ferment at 65 and increase to 68 during the last part of fermentation with Wyeast 1056. 

The part of my fermentation process that I feel least in control of is my O2 levels because I use a disposable tank and can only "measure" the rate by sight.  I've been going for 1 minute at a rate that turns over the surface of the liquid similar to a moderate rolling boil.  It's possible that I'm using too much or too little O2.  Could that be the issue?

I'm looking to take these beers to the next level and I feel like this is part of what's holding them back.  Certainly I've had some commercial beers where the alcohol was better hidden than in my attempts.  Any tips would be greatly appreciated.

[tschmidlin]

Do you use any yeast nutrients?

1056 will ferment cooler than 65 too, I assume that is the actual beer temperature and not ambient temp?

[hopfenundmalz]

You can come back about 8 to 10 hours later and give it another shot of O2.  The yeast need all the help they can get for big beers. 

Tom has a good point on the nutrients.  Get some zinc in there through the nutrients or yeast hulls.

[jlap]

I believe I did use some nutrient but I'd have to double check.  I usually use about half the recommended dose of the Wyeast blend.  Regarding a second dose of O2, I had fermentation after about 6 hours and the beer was to terminal gravity in 7 days.  I don't think the yeast is unhealthy or not growing enough as the beer is otherwise great.  I suppose I could try a second shot but I'm not sure why I'd be doing that...mechanism?  Too much O2 gives you hot alcohol right?

[nateo]

I've found a lot of the hot alcohol/solvent flavors in my big beers come from fermenting too hot. I would ferment a lot cooler. I try to hold my big beers under 60* (like 55-58*) for the first week or so, then let them warm up to fully attenuate.

[hopfenundmalz]

I believe I did use some nutrient but I'd have to double check.  I usually use about half the recommended dose of the Wyeast blend.  Regarding a second dose of O2, I had fermentation after about 6 hours and the beer was to terminal gravity in 7 days.  I don't think the yeast is unhealthy or not growing enough as the beer is otherwise great.  I suppose I could try a second shot but I'm not sure why I'd be doing that...mechanism?  Too much O2 gives you hot alcohol right?

6 hours is a short lag time, for sure. Once active fermentation is started, I might avoid more O2.

The reasoning is to give the yeast more O2, so they can build more sterols for reproduction.