Russian Imperial Stout with Bourbon Soaked Oak

I really enjoy a Whiskey Barrel Aged Stout.  For my money there is no better version than Goose Island's Bourbon County Brand Stout.  It is incredibly rich and flavorful and has a really profound bourbon character that no other beer I've tried has matched.  I've brewed a couple "bourbon barrel" beers previously (Bourbon Barrel Oatmeal Brown Ale & Bourbon Barrel Chocolate Imperial Stout) and, while both turned out okay, neither were particularly rich or boasted the sort of bourbon character that I had been after.

I have decided to look to the masters and attempt to brew up a proper clone of BCBS.  I'm going to use roughly the same grain bill used for the real BCBS which was generously published in this video (see 27:58):

This will be the biggest beer I've made so far with an OG of 1.129.  Given the size of the beer I'll be assuming a conservative ~60% efficiency.  To get 6 gal of this very sweet wort I'll need a huge 37 lbs of grain.  This is a lot more grain than my mash tun can handle.  To work around this I will do 2 mashes with half the grain in each. 

Each will have as much water as the mash tun will fit, probably about 8.5 gal.  I'll mash for 60 min at 155 F and then drain off the wort until I have 7 gallons in the kettle - this will be all the first runnings and then maybe a gal or so of sparge water.  I'll boil this for 2 hrs which will get me down to about 3 gal of wort.  In order to hit my gravity target I'll need the pre-boil wort to be at least 1.055 SG.  I think I should be able to hit this number pretty easily unless something goes seriously wrong with the mash.

Concurrently with this first boil I'll run the second mash with the other half of the grain.  I'll collect 7 more gallons from the second mash which will get me up 10 gallons in the boil kettle.  This 10 gal needs to be 1.078 or better to get 6 gal of 1.129 beer.  I'll boil this for 2 more hours or until the target gravity has been reached.

I'm going to bitter with 60 IBU of hops - I've chosen Magnum and Willamette to accomplish this.

For yeast I'm going with US-05 which I'm hoping will stop at around 12% ABV which will give me the desired 1.040 FG.  I'll ferment at 66 F.  I'm going to start fermentation in two vessels  to provide lots of head space which will hopefully limit my blow off losses.  Will combine the two batches after a week or two to let all the beer finish out together.

I do not have a used bourbon barrel to age this beer in unfortunately (no way in hell I could come up with 55 gal of this wort anyway).  Given that, I think the biggest challenge for this beer will be getting the right kind of oak flavor.  I've used Medium Toast Hungarian Oak cubes in multiple batches of beer and found that they consistently produce a wine like flavor (even when soaked in bourbon for extended periods).  The lack of the char that is put on the inside of a bourbon barrels is a very likely explanation for this (I credit the Bertus Brewery Blog for opening my eyes to this concept - also note two very helpful links:  HBT and Artisan Distiller).  To try to address this potential shortfall I've decided to make my own toasted and charred oak cubes (having control over the level of toast and the dimensions of the the oak cubes is exciting - I feel like this will just be scratching the surface in terms of possibilities with this batch)  I did this as follows:

• Bought a couple board feet of white oak from a local wood working shop

• Cut this into 6x0.75x0.75 inch pieces

• Toasted these in the oven at 450 F for 2 hours wrapped in foil (based on some research into the flavor contributions).  The oak really gave off a wonderful vanilla aroma during this toasting

Toasted vs Untoasted

• Charred these with a propane torch.  Put the fire out with a spray bottle

• Put the wood into a jar of Makers Mark Bourbon to take on some whiskey character and soften the wood character.  Let this age for several months prior to brewday

I will let the beer primary for 4 weeks and then I will cold crash it to drop the yeast.  I'm going to age this in a secondary fermenter (likely a bucket) with 1 or 2 sticks of oak for 6-8 months.

This is an ambitious project and will be a very long brewday.  I feel optimistic that I'm prepared enough and experienced enough to hit the desired OG number (my refractometer will be my friend in this process) - fingers crossed that I hit my FG number though.

Recipe Details:

• Grain:
• 24 lb 2 Row
• 8 lb Light Munich
• 1.5 lb Chocolate Malt
• 1.5 lb Crystal 60L
• 1.5 lb Roasted Barley
• 12 oz Debittered Black Malt
• 2 oz Acid Malt
• Hops:
• 2 oz Magnum (Pellet 14.1% AA) at 60 min
• 1 oz Willamette (Pellet 4.8% AA) at 30 min
• Yeast:
• 2 Packs of US-05 "Chico" Ale Yeast (2nd Pitch for one pack)
• Water:
• 20 gal Spring Water
• TBD gal Tap Water
• 2 tsp CaCl
• 2 tsp Gypsum
• 1 tsp Irish Moss at 15 min
• Extras:
• 4 oz Bourbon Soaked Oak
• Aged with 2 oz for 4 months
• Added 2 oz more for the remainder of the aging

Process Details:

• Batch Size:
• 6.5 gal - diluted to 7 gal (Target 6 gal)
• Mash:
• 155 F for 60 min
• Boil:
• 4 hrs (Target 4 hrs)
• Fermentation Temperature:
• 66 F
• Primary Duration:
• 4 Weeks
• Secondary Duration:
• 6-8 Months

Results:

• OG:
• 1.140 diluted to 1.130  (Target 1.129)
• Efficiency:
• 69% (Target 58%)
• FG:
• 1.046 (Target 1.040)
• Apparent Attenuation:
• 62% (Target 67%)
• ABV:
• 13.05% (Target 13.73%)

Brewing Notes:

• 1/28/18 - Brewday - 9:30 AM to 6:15 PM including setup and cleanup
• Heated 10 gal of water up to 185 F
• Milled half the grains.  Added half the CaCl and Gypsum to the grains

• Moved 6 gal to the mash tun - let the temperature settle for 10 min.  Ended up at 173 F.  Added 1 quart of cool spring water and stirred in.  Temp had settled down to 167 F after 10 more min
• Added the grain.  Stirred in well to eliminate doughballs.  Added the base grain first and then the specialty malts.  Mash Tun volume was a bit less than 9 gal with the grain and water.  Temperature was 155 F after adding the grain.  It had fallen to 154 F after 10 min.
• Mashed for 60 min.  Stirred the mash every 15 min - added 1-2 quarts of 200 F water prior to each stir to try to keep the temperature between 154 F and 155 (was successful for the most part).
• Added half a gal more 200 F water to get up the very brim of the mash tun
• At the end of the mash I vaurlaufed to clear the wort.  Measured the gravity of this sample as 20 brix which is 1.083

• Slowly drained the mash tun into the grant and pumped into the boil kettle.  Topped up the mash tun with more hot water as I went (Added 5 more gal of sparge water during the process).  

• Gravity in the kettle was 19 brix after collecting 3 gal.  Gravity in the grant was down to 15 brix at this point
• Started heating the kettle after collecting 4 gal
• After collecting 5 gal the gravity in the kettle is 16.6 brix and the gravity in the grant is 13 brix
• After collecting 7 gal the gravity in the kettle is 16 brix and the gravity in the grant is 12 brix
• Decided to use the last gal in the grant.  The increased me up to 8 gal of 15 brix wort.  So, I think I've gotten a bit more sugar out than I had anticipated
• Had the kettle to a boil once the sparge completed.  Set the timer to boil for 2 hrs.
• Added ~7 more gal of water to the boil kettle for the next mash and heated up to 200 F 
• Drained off the remaining wort from the mash into my small 5 gal pot.  Got ~2 gal of this.  The gravity of this wort is 8 brix.  I am going to include this in the next mash
• Cleared the grain from the MLT
• The boil started to slow a bit so I swapped out the propane tank part way through this first boil
• Milled the other half of the grains - added CaCl and gypsum

• Added second running to the mash tun - these were 135 F
• Added 200 F water up to 6 gal in the mash tun - this settled out at 163 F
• Added in the grain with 1 hr left in the first boil - stirred well to eliminate dough balls.  It turns out I forgot to add the 2 oz of Acid malt I'd set aside.  The temperature settled to 154 F.  I added 1 gal of kettle water at 190 F.  The temperature fell to 151 F in the mash tun.  I checked the temperature at the top and it was 158 F.  Decided to let it ride
• After half an hr of mashing I added a gal of 210 F water.  This raised the mash temp to 152 F at the temperature probe (was still 158 F at the top of the mash).
• With 15 min left I added another gal of hot water
• Drained my previous beer off the yeast cake for use in this batch.

• At the end of the 2 hr boil I had just about 3 gal of wort.  The gravity is too great for the hydrometer to measure (above 35 brix or so).  Target is 30 brix so I'm doing considerably better than the 58% efficiency on the first mash.

• Sparged slowly.  Added hot water to the top as I went
• Checked gravity on the vaurlauf sample and got 21 brix
• After a gal collected the gravity at the grant was 18 brix
• Collected pretty much all the first runnings - got 10.5 gal of wort.  Gravity of the final running's were about 10 brix.  Measuring the kettle gravity was not possible as samples taken from the bottom of the kettle were ~5 points higher than those taken from the top.  The top was about 18 brix and the bottom was 23 brix.
• Started the heat during the sparge.  Was a boil shortly after the completion of the sparge
• Boiled for 2 hrs
• The beer was amazingly frothy during the 3rd hr of the boil.  Had one pretty significant boil over where I lost maybe a pint of beer.  After than I was able to avoid further boil overs by adjusting the heat down when the foam got close to the top
• The second hr of the boil was much calmer fortunately
• With 1 hr left I added the bittering hops - had about 9 gal of wort at this point
• Rehydrated a second pack of dry yeast
• Added the 30 min hops
• Added Irish Moss at 15 min
• The beer measured 30 brix with ~7 gal of beer at 15 min.  I'm going to end the boil as planned
• Put the wort chiller in to sanitize with 5 min left
• Chilled the beer down to 70 F
• Transferred 4 gal of the beer into my SS Brew Bucket onto the second pitch cake and 2.5 gal into a better bottle with the new, rehydrated yeast

• Measured the gravity of the beer as 1.140.  So, I overshot my target OG by 8%.  I am going to add some spring water to get to 1.130 - this will require 0.5 gal.  Added 3 cups to the 2.5 gal portion and 5 cups to the 4 gal portion.  I verified that the new gravity was 1.130

• Moved these to the fermentation chamber set to 66 F
• 1/29/18 - The batch that went onto the yeast cake took off very quickly and is fermenting very vigorously this morning (~12 hrs after completion of the batch).  The portion with the fresh yeast hasn't started to show signs of fermentation yet.
• 2/2/18 - Fermentation has gone strong this week in both batches.  There is still quite a bit of airlock activity in both fermenters today (5 days out).
• 2/5/18 - My curiosity has gotten the better of me so I've taken a gravity sample 1 week out from pitching.  It is down to 1.050.  Still have a bit of airlock activity so I'd guess it will come down a bit more.  It is quite sweet and has a nice roast/chocolate flavor.  Also pretty boozy and rough at this point.
• 2/10/18 - Transferred the 2.5 gal from the better bottle to the main fermenter.  The krausen has mostly fallen from both of the beers.  Ended up collecting up to a bit less than 6.5 gal of beer.  Will give it a couple more weeks to finish up before transferring to secondary.
• 2/22/18 - Checked the gravity again - it is 1.048.  I think it has gone as far as it is going to
• 2/26/18 - Cold crashed the beer down to 32 F
• 2/28/18 - Added gelatin for fining
• 3/2/18 - Transferred the beer to a bucket fermenter with a vented silicone bung to secondary.  Added two toasted and charred oak sticks that had soaked in whiskey for several moths to age with the beer.  Ended up with a little more than 6 gal in separating it from the yeast cake.

• 4/1/18 - I moved the beer into a non-climate controlled room off the garage.  I hope the temperature changes through summer help draw out more oak and bourbon flavor 
• 4/12/18 - Took a sample.  The aroma has a pretty strong whisky and oak influence - very close to BCBS in the regard.  These come through in the flavor as well but it isn't anywhere near the levels in the real thing just yet.
• 5/3/18 - Took another sample.  Bourbon is barely perceptible in the aroma and not present at all in the flavor.  Not sure how that happened since there was a pretty pronounced aroma of bourbon and oak a month ago.  Otherwise the beer is tasting pretty nice - rich, smooth, and pretty complex with dark chocolate notes.  Will check on it in another month.
• 5/4/18 - Moved the beer into a room of the house that has been getting a bit warmer (70s-80s) in the hopes that heat will help the beer penetrate further into the oak in order to draw out more flavor.
• 6/15/18 - Took another sample which I've compared with the real BCBS.  The aroma of my beer has a bit of whisky but not quite as much as the real thing.  The flavor of mine is significantly less whiskey forward than BCBS.  More time with the oak is definitely needed.  Mine tastes nice at this point even when compared head to head with BCBS which I think is a good sign
• 7/8/18 - The beer has now been aging on the oak for a bit over 4 months so I'll do another side by side comparison between it and the real BCBS (2017 version).  Both beers have a very boozy aroma and both have a rich chocolate/coffee smell - the real BCBS has a stronger bourbon/oak presence.  Both beers have very pleasing and complex flavors but, just like last tasting, the flavor of the real BCBS has a lot more bourbon character than my version.  I don't think mine has picked up any more oak than it had last month and, based on this, I think it is unlikely to pick up much more over the next 4 months.  I could be happy with my beer but I really want that bourbon flavor that BCBS provides so I'm going to add two more sticks of oak that I've continued to soak in bourbon.

• 8/10/18 - 5 month mark tasting side by side with a 2017 BCBS.  Mine has picked up quite a bit of whiskey aroma after the addition of two more oz of oak.  Not quite as much as the BCBS but it has closed the gap.  Also a lot more whiskey flavor to my beer this month but still quite different than the BCBS.  My beer is quite a bit smoother than the BCBS.  Three more months to go.  Will be interesting to see how it turns out.
• 9/14/18

• 6 month tasting site by side with a 1017 BCBS.  In terms of aroma my beer is basically indistinguishable.  Both have very prominent and pleasant bourbon aroma.  Flavor wise they are still a fair bit different.  The BCBS has a much firmer bourbon bite than mine.  Mine has similar level of bourbon flavor but is quite a bit smoother in the finish with more prominent chocolate and coffee notes than the real thing.  Both beers are excellent.  Some theories regarding the differences:

1. Maybe the barrels have more really oaky/concentrated whiskey saturated than my sticks brought to the beer.  This could cause their beer to have more whiskey than mine
2. I soaked these sticks in 45 proof makers mark.  Whiskey is aged in the barrel at 60+ proof typically.  This 60 proof spirit is what is mixing with the BCBS.  The stronger spirit seems like a good candidate for the stronger bite in theirs.
3. I ended up 10 sg above the suggested FG.  It could be the sweeter/fuller body of the beer would change how the whiskey were perceived even if all other process details were creating the same whiskey character BCBS has.
• I plan to brew another one of these in October/November to try out some of these ideas
• I'll age this current batch for another couple months

• 11/2/18 - Bottling day - measured the FG as 1.046.  Bottled with 4 oz of priming sugar and some Primier Cuvee wine yeast.  Collected 6 gal of beer which got me 32 ~16 oz/~500ml bottles and 15 12 oz bottles.  Happy to have this one done!!
• 2/11/19 - Tasting Notes - This is a big, rich, and complex beer.  The base beer brought a real rich set of flavors which stand up nicely to the the whiskey and oak.  This was intended to be a clone of BCBS but I'm thinking I likely missed the mark a bit in terms of the strength of the whiskey character.  Even so I think the beer strikes a very nice balance of it's own.  I'll be brewing another one of these.
• 2/16/19 - Side by Side Comparison My Beer vs BCBS 2017

• Aroma:
• Both beers have a fairly pronounced whiskey and oak character but the BCBS has a more pronounced booze character.  I get a lot more chocolate and caramel malt out of mine than from the BCBS
• Appearance:
• The two beers are pretty much an exact match for color.  Carbonation seems about the same as well - about equal amount of head on an agressive pour.  The BCBS head lingers a bit longer than min.
• Flavor:
• My beer has bold set of malt flavors that then sort of fade into oak and whiskey.  The BCBS seems to be more whiskey and oak forward right out of the gate and malt is playing more of supporting role.  In the finish my beer has lingering alcohol presence, some malt, and a bit of hop bitterness.  The BCBS is a bit firmer in terms of alcohol burn and has a really lovely chocolate malt component that lingers.  A lot of similar flavors but the balance is quite different.
• Mouthfeel:
• The beers are very similar in terms of body and sweetness (full and slightly sweet).  Mine is a bit smoother where the BCBS is a bit prickly.  Both have noticeable alcohol warming.  BCBS burns the nose a bit when swirling it in my mouth.
• Overall:
• I think the major difference between the two beers is the intensity of the alcohol.  Both have a whisky and oak presence but the balance is shifted much more towards the whiskey with BCBS than in My Beer.  Both are pleasant but I think I prefer the balance struck by the real BCBS.  
• As an experiment I added some Whiskey mixed with a few drips of water to the mix.  The difference in terms of Whiskey character between my beer and BCBS is much less than the difference between BCBS and whiskey.
• 9/6/20 - Performed another vertical tasting comparing this beer to my 2019 version as well as the real BCBS.  The beer has held up very nicely.  I don't have too many of these left at this point.  I'll need to restrain myself if I'd like to have the opportunity to include it in a vertical tasting next year.

Lessons Learned:

1. I found that the temperature at the top and bottom of the mash were not equal for this beer.  I probably would have been better off recirculating this one
2. Found that the gravity at the top and bottom of the boil kettle were also quite different which made tracking of efficiency a bit tricker
3. The double mash worked out very nicely.  My timing of the cleanup from one mash to setting up an executing the next one fit very well within the 2 hr boil
4. I'm worried that my wort chiller may have formed a small leak.  I didn't get a good to drain it and I could have sworn that I saw a bit more dripping that is normal.  I need to test it before the next brew day.