I find a lot of the commercially brewed imperial souts to be far too sweet and cloying. In designing this recipe I therefore wanted to balance the inevitable sweetness that comes with a really big beer with enough hops to ensure that it did not taste like drinking alcoholic treacle. My plan was to aid in this by using Brett to dry out the beer beyond what Saccharomyces would be able to handle, as well as hopping quite generously to ensure a good balance of bitterness.
I brewed this beer as a parti-gyle brew with approximately half the sugars going into a more conventional stout and half going into this imperial stout, with only half the water. Thus the volume is half the size of my usual batch. I have adjusted the grain quantities to this half size to account for this. In designing the grist I had two goals, first to use large amounts of caramel malts to build body and complexity, and second to use up the last bits of various specialty malts that I had accumulated.
I hopped with Magnum and Newport for a total IBU of 50, which should be enough to balance the inevitable sweetness of such a big beer without the bitterness clashing with the roast character from the dark malts.
I brewed the beer in February 2015 and pitched the M03 yeast. After a month the gravity had dropped to 1.030 and the yeast acitivity had pretty much stopped. At this point I added the Brett claussenii, with the expectation that it would be able to do what the Saccaromyces could not, and eat up some of those complex sugars produced by the high amounts of caramel malts and the high mash temperature. It still took the Brett another 3 months to drop the gravity down to 1.018 and for me to consider the beer ready to bottle.
Pitch black and opaque even at the edges of the glass, the beer looks every part the imperial stout. The tan head is quite insubstantial and the low carbonation means you don't get much of it.
A mild, earthy funk of olives, farmyard and citrus combines with the sweet, coffee and smoky character of the roast malts. The funkiness of the beer has gradually increased as it has conditioned in the bottle, but even now, 6 months after bottling, it is not particularly strong.
The body is thick, with the slight carbonation providing only a tiny bit of lightness. There's alcohol here for sure, 9.7% ABV can't easily be hidden. But there's also lots of dried fruit and coffee. Above it all there are hints of spices and citrus and olives, perhaps from the Brett.
I'm very happy with how this turned out. The funk of the Brett melds well with the other flavours in the beer and has produced a very tasty, heavy beer, perfect for a winter evening.
Batch size: 10l
Expected OG: 1.095
Expected FG: 1.020
Expected ABV: 9.7%
Colour (SRM): 41.9
50.7% (2.25 kg) Pale Ale Malt
11.3% (0.50 kg) Munich Malt
11.3% (0.50 kg) Flaked Spelt
5.6% (0.25 kg) Toasted Oats
5.6% (0.25 kg) Flaked Wheat
4.8% (0.22 kg) Roasted Barley
3.4% (0.15 kg) CaraPils
2.3% (0.10 kg) CaraAmber
2.3% (0.10 kg) CaraBelge
1.7% (0.08 kg) Black Malt
1.1% (0.05 kg) CaraAroma
Magnum (9g / 20 IBU) @ 60 min
Newport (20g / 20 IBU) @ 15 min
Newport (25g / 10 IBU) @ 5 min
Mangrove Jack's M03 Newcastle Dark Ale
Wyeast 5151-PC Brettanomyces claussenii