#67 Koschei Imperial Stout

Eureka, this is by far the most insane batch I have ever made and probably the last post for this year. Plus a recipe brewed not so long ago like the ones I posted recently… Anyway, I am a big fan of Imperial Stouts and I am still working on some recipes to get myself a really great example of the Imperial Stout style. Sure I have made some really tasty examples in the past such as two versions of the legendary Rusalka Imperial Stout. I even did a re-brew of the Rusalka Imperial Stout and let a part of if mature on Islay Whisky soaked wood chips. I added the Whisky to get yet another flavor compound. Islay Whiskys are well-known for their peaty character. The distillers on Islay (a small Scottish island) use peat to dry the green malt. This gives the Whisky a very peaty, smokey and phenolic taste. You either love or hate it. And I really, really like this character in the Islay Whiskys. Luckily for me, I can get my hands on some Islay malt. The smokiness you get from this particular smoked malt is very distinct to the one you get from the normal Bamberg smoked malt (Weyermann Rauchmalz). The smoked malt from Bamberg has huge smoked ham character. The Whiskymalt adds a very subtle smokiness to your beer. And not the overpowering smoked ham character. I will certainly post the tasting notes of the Whisky soaked Imperial Stout in the future.

Back to the Koschei Imperial Stout. Instead of just going with some unique malts or any other unusual ingredients to improve the aroma and flavor profile of an Imperial Stout, I used a different approach: Higher alcohol content. Alcohol can influence a character of an Imperial Stout in many ways. If the alcohol is not boozy but well incorporated in a beer it can help to improve the whole character of a beer. I basically used the Rusalka Imperial Stout recipe and went from there. I first added additional base malts to increase the original gravity and then adjusted the roasted malts. My target original gravity was around 27°P without any additions of sugars. I wanted to get an all malt Imperial Stout here. However, the lower efficiency forced me to add some sugar to get to the target original gravity…

About the name Koschei. I keep naming all my Imperial Stouts after dark characters from the Slavic mythology. Further information about the Koschei character can be found on Wikipedia. Lets have a look how my recipe for the Koschei Imperial Stout looks like:

Recipe: Koschei Imperial Stout
Numbers: Volume [L] 51 (13.5 gal)
Original gravity 27.4°P
Terminal gravity 7°P
Color Around 230 EBC
IBU 86 IBU
ABV > 12% (v/v)
Grains: Pale malt (6.5 EBC) 19.6 kg
Wheat malt (4 EBC) 2.5 kg
Roasted barley (1150 EBC) 3.15 kg
Carafa 1(900 EBC) 3.15 kg
Cara Munich 2 (120 EBC) 1.1 kg
Brown sugar (0 EBC) 2 kg (added during primary fermentation)
Hops: Northern Brewer (10% AA) 134.8 g and boil for 90 min
Northern Brewer (10% AA) 103.7 g and boil for 30 min
Northern Brewer (10% AA) 50.8 g and boil for 15 min
East Kent Goldings (5.1% AA) 156.7 g and boil for 15 min
East Kent Goldings (5.1% AA) 233.1 g and boil for 3 min
Yeast: Wyeast’s #1086 Irish Ale
Water: Burgdorf Mash: 26 L (6.9 gal),
sparge: 20 L (10.6 gal) @78°C (172°F)
Rest: Mash in @65°C (149°F),
90 min @65°C (149°F),
10 min @ 78°C (172°F)
Boil: Total 90 min
Fermentation: Primary 11 days @20°C (68°F) in plastic fermenter
Secondary In Whisky oak barrel for 5 months
Maturation: Carbonation (CO2 vol) 1.5
Maturation time Months to years

Fig 1: Koschei mash

10/14/12: An insane brew day begins with milling roughly 30 kg of malts (66 lbs). I had to mash-in in three different kettles! I filled my 50 L kettle (13 gal) and two other kettles with a volume of approximately 20 L of mash (5.3 gal) each. This made my wonder how I sparge such a huge amount of mash later on. Anyway, I left the mash rest at 65°C (149°F) for 90 min. I chose a lower temperature range for the rest to decrease the body of the beer later on. After the 90 min rest, 10 min rest at 78°C.

I then transferred the whole mashes from the two smaller kettles in my lauter kettle (50 L, 13 gal) and sparged the first part of the mash and collected the runnings in a kettle. I stopped sparging as the kettle (25 L, 6.6 gal) was full (Fig 2). The color of the wort was already very, very black. I then emptied the lauter kettle and filled it up with the second part of the mash and collected the runnings until the 50 L kettle was full. I then went on collecting the runnings until half of another 25 L (6.6 gal) kettle was filled.

Fig 2: Koschei first runnings boiling

Once all the three parts of the worts were boiling, I added the hops according to the recipe above. I split the hops between the kettles based on the volumes.

Because I am very inquisitive, I could not stop to collect further runnings from the lautering kettle and measured the gravity. I was surprised, the original gravity was still at around 12°P (1.048). I therefore filled another kettle with the third runnings. I used these runnings for batch #68. Will post about this experiment in the future.

After the boiling time of 90 min was over, I cooled the wort down to approximately 22°C and pitched a huge yeast cake of Wyeast’s #1084 Irish Ale I had from a previous batch of Imperial Stout. The fermentation started after several hours already.

Fig 3: Filling a Whisky barrel with Koschei Imperial Stout

25/10/12: Racked the beer off the huge yeast cake directly into a small Whisky barrel (Fig 3). I recently bought a small barrel (50 L, 13.2 gal) which was custom-made for me. The wood for the barrel is from a real full size Whisky barrel. The wood is therefore not fresh anymore and soaked in Whisky. I had a huge smile on my face when I got the barrel and unwrapped it: The Whisky smell was insane. Unfortunately, the barrel was not filled with an Islay Whisky. So no peatiness… Anyway, I got the barrel just a day before and rinsed it with some water first and added a shot of Bunnahabhain’s Darach Ur Whisky (Bunnahabhain is an Islay distillery with the characteristic peatiness) to kill any kind of bad microorganisms in there. Next step, I flushed the barrel with carbon dioxide to displace any oxygen in the barrel.

Then added the fresh Koschei Imperial Stout. I even had to add another 10 L (2.6 gal) of a maturing Imperial Stout from another fermenter to fill the barrel. However, the barrel wasn’t filled up to the top after that as well. Adding water or anything else was no option since I do not want to dilute my Koschei Imperial Stout any further anyway. I keep my fingers crossed and hope no complications occur because of the small headspace in the barrel… Depending on how fast the wood and Whisky character are detectable in the beer, I might have to fill the barrel to the very top and leave the beer in there for several months.

Fig 4: Koschei Imperial Stout in Whisky barrel. Maturation in progress… Some sour beers in the back

11/01/12: Beer now one week in the barrel. Time for a first tasting. The beer has some very subtle chocolate, coffee as you would expect from an Imperial Stout. However, not very overpowering at this stage. Some alcohol was in the nose as well. What about the wood/Whisky? To be honest, I could not tell whether this beer matured in a Whisky barrel for a week or not. No wood or Whisky character in the nose. A first sip. And again, not a lot of wood barrel character. Just the normal stuff you would expect from a young Imperial Stout like chocolate, coffee, alcohol, bitterness. But not a lot of the Whisky and barrel. It seems the maturation will go on for some time. This gives me the opportunity to think about another batch to refill the barrel after the Imperial Stout…

22/12/12: The beer is now roughly two months in the barrel. Seriously I had to taste the beer from time to time and it is quite interesting to taste the changing character of the beer over time. The appearance is really dark and very oily. There is already a lot going on in the nose. I can detect lots of chocolate, coconut, vanilla and some alcohol as well. All in all a really nice nose already. What about the taste? Chocolate again, a hint of smoke, pepper, a decent bitterness and it finishes with a chocolate, coffee, bitter, roasted character. Maybe some cardboard in there as well… Warming sensation of the alcohol. The only thing that I am not really sure about is if the beer is oxidized. I am not sure if the cardboard taste originates from oxidation or from a different source. In addition, the beer is flat and it is hard to foresee how the carbonated version might taste like.

The beer is on the right track in my opinion. It seems that it the beer can handle some further maturation in the barrel. I am really looking forward to taste this beer in a couples of years in the bottle already… Stay tuned for further updates concerning this batch.

I am not sure if I post another post before Christmas or even before the end of this year. I therefore wish you all a Merry Christmas and happy holidays. I hope you can find some time to relax and enjoy the upcoming days with family and friends. Or find some time to brew… I will certainly be back with new posts in January and some really interesting stuff for sure. Cheers, Samuel

Update:

03/29/13: Bottled part of the batch to a carbonation level of 1.5 vol of carbon dioxide. Beer spent roughly 5 months in the Whisky barrel. Remaining shares of the beer mature in kegs for further uses.

12/29/13: Tasting notes published

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2 thoughts on “#67 Koschei Imperial Stout

  1. Oh you have got to be kidding me!
    I absolutely LOVE Islay Whiskys! Best of the best! Lagavulin, Caol Ila, Laphroaig, Bowmore… Awwwww… In fact I have a bottle of Quarter Cask Double Cask Matured Laphroaig sitting right here waiting to be opened and tasted 🙂 Good taste man, good taste…

    • Hehe :-), luckily my brother just visited Islay a few months ago and brought some really great Whiskys back. So I am slowly getting into new Islay Whiskys. Lagavulin 16 is really amazing! As a side note, we tasted Epic Brewing Smoked & Oaked Belgian-Style Ale last week and this beer has damn close to a Whisky. Seriously, a really amazing beer.
      Cheers, Samuel

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