Beer from the wood

The term "beer from the wood" once meant the cask ales produced by a handful of English brewers - Sam Smith, Theakston and Wadworth - who prefer to use wooden containers rather than metal ones. The expression has taken on a wholly new meaning today with the development of wood-aged beers in both Britain and the United States. The scene was set by Innis & Gunn's oak-aged beers, which are matured in American Bourbon whiskey casks. Two further Scottish brewers are now making "whisky beers". Tullibardine 1488 (7%) is brewed by Traditional Scottish Ales and matured in oak casks used to make single malt whisky. Paradox Islay Cask (10%) comes from Brewdog in Fraserburgh and uses casks that have produced such delights as Laphroaig single malt.

The Scottish beers are all available in bottle and Paradox can also be found in cask-conditioned form, though at a lower strength.

The essential difference between the likes of Sam Smith's or Theakston's bitters and the new breed of beers is that the former use fresh wood that is thoroughly cleaned each time the casks are filled and impart no woody flavours to the beer while the new styles deliberately encourage oak and whisky characteristics to impregnate the ale.

Dougal Sharp, former head brewer at Caledonian in Edinburgh, founded Innis & Gunn as a result of an experiment with whisky maker William Grant in 2001. Grant had bought some beer from Dougal to make a whisky matured in wooden casks. The aim was to use the beer to season the casks and then pour it away. But a year later William Grant's tasters found that some of the beer had been left in cask and tasted superb.

As a result, Dougal left Caledonian and founded Innis & Gunn. He brews a 6.6% beer that is then matured for 77 days in American white oak casks. The casks are bought from American Bourbon makers: in the United States, Bourbon casks, which are lightly toasted, can be used just once. They are then broken up and sold to other distillers. Scottish single malt whisky is matured either in Bourbon or sherry casks. Dougal spoke at a seminar on oak-aged beer organised by the British Guild of Beer Writers in the autumn at Thornbridge Brewery in Derbyshire. He is adamant that the flavours found in his beer - vanilla, butterscotch, citrus and honey - come from the wood, not from the Bourbon whiskey. It poses the question: which comes first, the wood or the whiskey? There is no doubt that the aromas and flavours found on Tullibardine and Paradox are profoundly influenced by the original whisky.

The keynote speaker at the seminar was Garrett Oliver, brewmaster at the Brooklyn Brewery in New York City. There are now so many American craft brewers maturing beer in wood that the Great American Beer Festival has added wood-aged categories to its awards.

At Brooklyn, Garrett matured a stout in Bourbon casks. The casks were lightly rinsed, though some American brewers do not rinse casks at all. For the first three months of maturation, Garrett said, the flavour of the beer "was all about Bourbon. The beer flavours take longer to influence the liquid."

Theakston's cooper Jonathan Manby attended the Thornbridge wood-aged seminar and showed the assembled beer writers the art of building a cask made of oak. Jonathan is the last cooper to have served his apprenticeship. A century ago thousands of coopers built casks in the British brewing industry but Jonathan is likely to be the last of the line.

John Keeling, head brewer at Fuller's in West London, said many more British brewers would like to produce "whisky beers" but they run foul of Customs & Excise. Dougal Sharp has encountered no problems in Scotland, where the excise officers accept that the strength of Innis & Gunn comes from fermentation, not from whiskey. But their colleagues in England are not so easily convinced.

John has experimented with maturing London Pride, Vintage Ale and 1845 in Glenmorangie single malt whisky casks. The results were so encouraging that Fuller's wanted to make them available commercially but were thwarted by Customs & Excise. The tax men declared that if the beer had increased by 0.5% in strength as a result of the maturation process - known as "grogging" - then Fuller's would have to apply for a spirits licence and the beers would be taxed accordingly.

John bought some samples to the seminar. We were able to taste an 8.5% 1845 with a smoky and whisky aroma, sweet fruit and malt in the mouth and a bittersweet finish packed with fruit and grain. An 11.75% version had been matured in Jim Beam casks and had a rich Bourbon nose, with sultana and raisin fruit, more burnt fruit and whiskey in the mouth and a dry finish with fruit and vanilla. Finally we sampled a 12.25% beer matured in Glenmorangie casks. It had a blood oranges aroma, a smooth vanilla and fruit palate, with smoky, woody and fruity notes in the finish.

Thornbridge Brewery has also experimented with maturing its 7.7% St Petersburg Stout in whisky casks. We were also able to taste its 10.3% barley wine, matured in cask for two months, and fermented with yeasts from Thornbridge, Kelham Island and Brooklyn. This amazingly rich beer had an aroma of plums, marzipan and lime marmalade, with ripe fruit and hops (Magnum and East Kent Goldings) in the mouth and a dry finish dominated by tart fruit and hops.

Last month the Goose Island Brewery in Chicago staged a festival entirely devoted to wood-aged beers. There were 70 beers from 30 breweries. A wood-aged movement is under way but we have some work to do with Customs & Excise in England, who are building road blocks to progress.

*Innis & Gunn has now added a beer matured in rum casks to its portfolio.