Batch 67: Tart of Darkness clone sour stout with Black Raspberries and Cocoa Nibs

A friend came into a 53 gallon Knob Creek Single Barrel Reserve 9 year whiskey barrel that now lives in my basement and houses homebrew.  We’ve done a Russian Imperial Stout, a Scotch Ale, and an Oud Bruin.  The fresh barrel contributed a massive oak character, but over 3 batches and 1.5 years, the oak faded.  When the barrel naturally went sour during the Scotch Ale, we switched to intentionally soured beers and added 8 sachets of the Flemish Ale F4 blend from Blackman Yeast.

Next up is a sour stout, very low on hops (<10 IBUs), inspired by The Bruery’s Tart of Darkness.  The low IBUs are friendlier to souring microbes and also avoid the clashing of bitterness and acidity.

6/5/16: I brewed 4 shares (22 gallon batch), 3 for the barrel and one to drink clean.  I actually ended up with more like 24 gallons at slightly higher than intended gravity due to good efficiency.

First chilling: I ran off the first 16.5 gallons through the plate chiller as a low-bitterness stout for souring.  This had an OG around 1.062.

Second chilling: I then kept boiling the remaining beer with a final hop addition of 0.89oz Zythos and 0.25oz Galena for an hour, then added an ounce of Mandarina Bavaria at 5 minutes.  My volume barely covered my heating element, and I was concentrating the wort with a second hour of boiling, so to compensate I topped up with some final running set aside from the end of my fly sparging.  This left me with about 7 gallons of hoppier, more balanced, clean American stout.  OG 1.064, and about 40 IBUs (compared to less than 10 IBUs for the souring shares).

I fermented two of the shares for the barrel with US-05; the third barrel share, plus my hoppy stout, got a yeast cake of Wyeast 1968 London ESB Ale stored in the fridge from my Bellaire Brown clone.  The dormant yeast cake was awoken in a 3L yeast starter, but only had ~20 hours to ferment on a stirplate.  I have some concerns about low attenuation of this yeast on the hoppier stout, especially given the high mash temp (157F).  That is desirable for the sour share, to give the barrel’s microbes more to work with, but I may need to pitch additional yeast to fully ferment the clean beer.

6/13/16 (8 days): both yeast variations are at about 1.020, having fermented in the low 60s unattended.  The ESB yeast has flocculated considerably more.  I racked some of the yeast cake from under a US-05 fermenter into the ESB fermenters, roused all of them, and moved all to a warmer room.

November 2016: all of my primary fermenters developed an unpleasant infection.  The barrel needed my 15 gallon contribution, so I pasteurized it by heating it to about 150F for 30 minutes.  Lifting the lid of the boil kettle was quite harsh – I’m not sure if that was CO2 or alcohol coming out, or both.  The resulting product tasted off, but at least no unwanted bugs are going into the barrel and ruining it permanently.  And actually, a sample from the barrel at 5 months tastes great: slight brett, firm sourness, pleasantly fruity.

My shares not destined for the barrel also got infected and ended up undrinkable.  My guess is that the culprit was the reused yeast; I wasn’t fastidious in how I captured or stored it.  And then I racked back and forth between fermenters, blending to address attentuation issues, which would have introduced the bacteria to all of the vessels.  Bah.

January 2017: the stout was pretty good when we drained it from the barrel.  I put mine on a 1/2 lb of cocoa nibs I wanted to use up, plus 3 lbs of wild-picked black raspberries I froze last summer.

May 2017: Kegged the beer – at this point, it’s a deep purple color from the black raspberries.  The chocolate note is perfect, varying sip-to-sup from subtle to dominant.

September 2017: this beer (with cocoa and black raspberries) won 1st place in American Wild Ales at the Michigan Beer Cup!  Even better, it also won 2nd – Ryan Bruder won silver with his variant with cherries.

At some point I added about a gallon of other beer to the keg to cut the sourness, mostly some bottles of a boring imperial stout I recently brewed, along with 3 vanilla beans to accentuate the chocolate.  This is where kegging has a major advantage.

I served this beer through a Randall filled with coffee beans at the AABG summer party, the Beer-B-Q.  The coffee aroma was off-the-charts intense.  I personally thought the blend of coffee, fruit, and tartness was lovely; it weirded out many others, though.  This variant is not immediately identifiable as beer – it’s pretty far out there.  Coffee and dark sours is a combo I plan to try again.


Here’s the recipe (below and on Brewtoad): Tart of Darkness clone

Recipe Details

Batch Size Boil Time IBU SRM Est. OG Est. FG ABV
22 gal 60 min

Fermentables

Name Amount %
2-Row Brewers Malt 38 lbs 76
2-Row Caramel Malt 60L 4 lbs 8
Oat Flakes 4 lbs 8
Roasted Barley (UK) 2 lbs 4
Chocolate (US) 2 lbs 4

Hops

Name Amount Time Use Form Alpha %
Galena (US) 0.75 oz 60 min Boil Pellet 13

Miscs

Name Amount Time Use Type
Whirlfloc Tablet 2.0 5 min Boil

Yeast

Name Lab Attenuation Temperature
Blackman F4 Flemish Blend 85% 32°F - 32°F
Safale US-05 Fermentis 86% 32°F - 32°F
London ESB Ale Wyeast 69% 32°F - 32°F

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