There's something about Imperial Russian Stouts that gets brewers excited. "It's an incredible beer style," says the Boatrocker Brewery's Matt Houghton of this strong, complex, inky-black beer. "There's so much you can do with them; they don't have to be intensely roasty, you can go a number of ways."
Drinkers are increasingly of the same mind. In the most recent Hottest 100 Craft Beers poll run by the Local Taphouse, seven IRSs appeared, compared with just one last year. "There's a trend towards more interesting, higher-alcohol beers," says Guy Greenstone of the Local Taphouse. "Imperial Russian Stout is among the most interesting. It can be so complex."
The style's history is pretty fascinating, too. First brewed in London during the 18th century for export to Russia, where it found favour at the court of Queen Catherine the Great (hence the name), it has recently enjoyed a worldwide revival on the back of its popularity among the beer cognoscenti in the United States.
The key reason it's so well-loved is the flavour; Imperial Russian Stout offers chocolate, licorice, dark coffee, dried fruit, roasted and burnt flavours, and much besides. It's dark - like liquid tar - and strong, the perfect type of beer for autumn and winter, even in Australia's distinctly non-Russian climate.
"It's definitely something you look for at this time of year," says Houghton, whose brewery can be found in Braeside. "It's a psychological thing: you want a beer that's more malt-based, more robust. It's the season for something more hearty."
Boatrocker's own Imperial Russian Stout, Ramjet, was aged for a few months in whisky barrels that had been used by the New World Distillery in Essendon. It was one of the seven that featured on the Hottest 100 list, a number that also included an Imperial Russian Stout brewed by the Mornington Peninsula Brewery. Head brewer Andrew Gow says it was influenced by the beers he drank on a trip to the West Coast of the US in 2012. "It's quite heavily hopped," he says. "I tried a lot of dark beers in the US that had a lot of hops, and I really liked them."
That beer - made using the citrus-and-melon-accented American hop Amarillo - was named best stout at last year's Australian International Beer Awards.
As Gow suggests, Imperial Russian Stouts can change and improve with age. Courage Imperial Russian Stout, a direct descendant of the original IRS, has recently been revived by the Wells and Young's brewery in England. Wells and Young's International Brewmaster Jim Robertson, who began his career with Courage in its old brewery by Tower Bridge in the late 1970s, remembers how aged Imperial Russian Stout was so prized it became part of a unique Christmas tradition.
"Every Christmas, the brewers got together in the sampling room, all dressed up, at noon on Christmas Eve," he says. "The head brewer would produce a 13-year-old magnum of Russian Stout and a 13-year-old magnum of vintage champagne, and the two were mixed together in an old enamel jug in the sample room to form the brewer's Christmas Black Velvet."
Drinkers are likely to see more of it in the years to come, according to Houghton. "There hasn't been the opportunity to brew large volumes of beer like this before," he says.
"It would sit around for too long, not enough people were interested. With the new interest amongst the general public, we can start making more of these interesting, stronger beers."
FIVE TO TRY
Moondog Jumping the Shark ($23 for 375ml, 15.5 per cent ABV, slowbeer.com.au)
Suitably rich (it was brewed with $4000 worth of Tasmanian truffles and aged in cognac barrels), lots of dried fruit.
Boatrocker Ramjet ($11 for 330ml, 10 per cent ABV, slowbeer.com.au)
Subtle whisky and wood character.
Mornington Peninsula Imperial Russian Stout ($8 for 330ml, 9.5 per cent ABV, slowbeer.com.au)
Classic flavours of coffee and chocolate married to an impressive hop punch.
Brooklyn Black Chocolate Stout ($10.50 for 355ml, 10 per cent, beercartel.com.au)
Decadent; lots of rich chocolate.
De Molen Rasputin ($14.67 for 330ml, 10.7 ABV, beercellar.com.au)
From a Dutch brewery known for rich, liquorice-heavy stouts like this.
WHAT TO EAT
Depending on what you're drinking, IRSs can work wonderfully with oysters, blue cheese, beef stews (particularly if you make the stew with the same beer), rich chocolate puddings and vanilla ice-cream.