Hot Rocks, Innis & Gunn

Innis & Gunn Hot Rocks 7%

Edinburgh brewer Innis & Gunn – famous for its oak-aged beers – has turned back the centuries with a bottle-conditioned beer that recalls the ales drunk as long ago as 4,000BC. The beer’s name comes from the use in Neolithuic times of placing searing-hot granite rocks in the fermenting beer to caramelise the brewing sugars for colour and flavour.

In order to recreate the 6,000 year-old recipe, Innis & Gunn used evidence gleaned from ancient archaeological artefacts, including shards of Neolithic pots found in the islands of Orkney and Rum in Scotland. The beer is brewed with raw barley and malted grain and also the ancient bere barley still grown on Orkney and used to make bread there. As hops were not used widely in Britain until the 1500s, Innis & Gunn – like ancient men and women – used no hops in Hot Rocks. But, in keeping with ancient tradition, sweet gale and meadowsweet have been added to balance the grain as well as horehound and pink heather, all naturally-occurring botanicals in the British Isles since 4,000BC. The beer also has a touch of honey – not commonly used in brewing until Victorian times – to lend a soft sweetness.

Dougal Sharp, founder and chief executive of Innis & Gunn, says: “I started Innis & Gunn in 2003 to experiment with flavour and make beers, using traditional and innovative methods, which are highly distinctive for their depth of flavour. In making Hot Rocks, we’ve gone deep into the back catalogue of British brewing, taking archaeological evidence dating back 6,000 years of the earliest ale known to have been made in the British Isles and mashing it with all our brewing experience to create a less rough-and-ready, more refined brew for the modern day, with an ABV to match.”

Merryn and Graham Dineley, the Orkney-based experts on ancient and traditional brewing, say: “We think the recipe is spot on, a proper prehistoric ale. It would do for an ale made in Neolithic, Bronze Age, Iron Age or Viking times as well. Hot rock heating of water is fascinating, though it’s quite hard to boil the water despite the hissing and sizzling of the rocks.”

The beer has a hazy gold colour, with a spicy, herbal aroma with hints of cinnamon, honey and toffee. The palate is sweet but not cloying with clean, “fresh bread” grain balanced by spice and honey. The finish lingers and is a complex mix of honey notes, spices, toffee and rich grain. It ends surprisingly dry and is wonderfully refreshing.

Hot Rocks was brewed by the Brewing Research Institute at Chipping Camden in Oxfordshire. It’s a limited edition beer and is available from the brewery shop for £15 for 330ml bottle, free shipping. www.Innisandgunn.com

As the beer is bottle conditioned, it can be laid down for drinking in the future – “but not for 4,000 years!” Dougal Sharp says.