Quest for the "BIG" Beer

A few months ago after watching an episode of Brew-Masters on the Discovery Channel, I learned about Dog Fish Head's 120 IPA.  When it comes to unusually large brews I know that Dogfish head's 120 weighs in at an 18% and Sam Adams has Utopias at 25%, neither of which I have tried (can't get them here in Arkansas), but with all the hype about these unusually "Big" beers I've set my sights on brewing something around 15-20%.  So I set out to create a recipe with big enough grain/hop bill to keep up with the increased amount of alcohol.  With this much alcohol we are pushing the limits of typical beer yeast.

Brice stirring the mash

Recirculating the mash

The biggest challenge this beer brings to the table is getting it to completely attenuate.  Attenuation refers to the ability of the yeast to completely eat the simple sugars in the wort and is usually expressed in percentage.  When brewing an "all grain" beer there are many things going on at once.  So it's always nice to have a brew partner to help.  I asked my friend Brice to come and assist.  Brice was actually the one who got me started with brewing beer in the first place.  After tasting his home-brew I knew I had to start and after that first extract kit I was hooked.  With a strike temp of 166F, we hit our target temp of 152F and successfully held there for the 60 min mash.  Because this brew required so

Heating the sparge water
(Yes it does take a while
on the electric stove)

much grain (16.5 lbs) we had to try and avoid getting the mash too thick by not using enough water (Mash 1qt/lb: Sparge ~2 qt/lb).  So we decided to only do one round of batch sparging.  Although I like to do two rounds of sparging, I only have a 10gal brew kettle, so I can really only boil 9 gals max and that's with special attention to boil-overs.  Even with only one batch sparge, we ended up with 91% efficiency, which is my best efficiency on record and is amazing considering the amount of grain used.  I've got to give kudos to the Brits with their well modified Maris Otter malt.  Even though it is more expensive, ever time I use it I end up getting great efficiency and it has a great flavor.

Boil over management

We added the bittering hops as soon as we got to a rolling boil and managed the boil over.  Thanks to Brice continually stirring and adjusting the gas, we didn't end up with a boil over.  While he was keeping an eye on the boil I went in and cooled off a hydrometer sample to see where we were at.  As I mentioned previously we got 91% efficiency on the mash so ended up with hydrometer reading of 1.060 before the boil. 

Celebration of the finished boil

Aerating the wort and making the starter

We started with 9 gallons before the boil in order that we might have closer to 5.5-6 gallons left after a 90 min boil.  Since this beer is so big we will be fermenting it with two different strains of yeast.  One strain (US-05) will be used first for the flavor profile up to 11% (its alcohol tolerance) then 5 days or so into fermentation we will use the second yeast strain (WLP099-High Gravity Yeast) to finish attenuation.  We will be taking 0.5gal from the finished wort to use as a yeast starter on a stir-plate for the high gravity yeast.  After we finish the boil, time to pull a hydrometer sample and check the OG.  We ended up around 1.076.  So you might say that's nowhere near high enough to get 15-20% and you would be right, but the secret to this brew is dextrose additions during fermentation.  The thought is that adding dextrose during fermentation helps feed the yeast into continued fermentation and will help it attenuate fully.  On second day of fermentation I started adding the dextrose 8-12oz 3 times a day. The goal is to have 12lbs of dextrose added to the beer over the course of  14 days.  After aerating the wort and pitching the yeast in both the starter and in the carboy, we put the carboy in the fridge at about 63F.

Dextrose additions

The next morning (8 hours later) we have liftoff.  Active fermentation going in the carboy and in the starter.

Adding Dextrose

Ended up adding a total of 14lbs of dextrose over the course of 14 days (FG at 1.028 and 16.5% ABV).  At 28 points it is still a little sweet but workable especially since with the added sugar that's about 81% attenuation.

Below is the dextrose addition schedule i used:

3/26 - fermenting
3/27 - added 1.5 lbs dextrose 3 additions of 8oz
3/28 - added 1.5lbs dextrose 3 additions of 8
3/29 - added 2.3125 lbs dextrose 2 additions of 8oz, 12oz, 9oz
3/30 - added 2 lbs dextrose 1 additions of 8oz 2 of 12oz
3/31 - added 2.25 lbs dextrose 3 additions of 12oz
4/01 - Nothing added
4/02 - added 0.5 lbs dextrose
4/03 - added 0.75 lbs dextrose 12oz
4/04 - added 0.75 lbs dextrose 12oz
4/05 - Nothing added
4/06 - added 0.5 lbs dextrose 8 oz

4/07 - added 0.5 lbs dextrose 8 oz

4/08 - added 0.5 lbs dextrose 8 oz

4/09 - added 0.5 lbs dextrose 8 oz

4/10 - added 0.5 lbs dextrose 8 oz

Transferring to Keg

 I transferred the beer to the keg.  I'm planning on lightly force carbonating (about 1-1.2 vols).