There’s an odd feeling, like you’re doing something slightly illegal, when drinking and discussion beers that would have been poured down the drain by every generation of brewers before this one for being irredeemably faulty. But 21st century brewmasters have discovered the flavour found in wood, and declared it good.
Unlike wine-makers, especially many white wine makers, and distillers, especially whisk(e)y distillers, brewers who have used wooden fermenting vessels and wooden casks always made it an axiom not to have any influence from the wood apparent in their beers. Wood flavours were fine in chardonnay, or scotch, but not in IPA or porter.
Oak for casks, vats and brewing vessels was sourced from places such as Russia and Poland that were known for growing wood that would not impart any flavours to the beer. Casks were lined with “brewer’s pitch”, vats were scrubbed down so that when stock ales, porters and stouts were being matured in them, no tang of the timber would come through into the beer. Once fermenting vessels began being lined with metal, and steel and aluminium casks came in, wood flavours disappeared as a worry.
The introduction of wood flavours as a desirable characteristic, in the UK at least, was a serendipitous discovery springing from the wish of the Scotch whisky distiller William Grant in 2002 to add to its range of “cask reserve” whiskies, all finished off in casks that had previously held other alcoholic drinks, such as sherry or rum. Grant’s wanted a beer to fill casks with and enable it to make “ale cask reserve” whisky once the beer had been emptied out.
Dougal Sharp, then of the Caledonian brewery in Edinburgh, designed a malty, estery, sweet, not very hoppy beer he and Grant’s felt would give the casks a good foundation for maturing whisky in. The beer was aways meant to be thrown away once it had been in the casks long enough to impart flavour to the wood that could be absorbed subsequently by the whisky. But workers at Grant’s distillery sampled the beer, and liked the oaky, vanilla flavours it had picked up from the new wood so much that instead of disposing of it they started taking it home …
Intrigued, Sharp tried putting the beer into a blind tasting at the brewery, where it scored a consistent nine out of nine with the tasters. The “tweaked” version of their original brew for Grant’s that Dougal and his father Russell launched in 2003 as Innis & Gunn Oak-Aged Beer has been so successful subsequently it has effectively launched a completely new category in the UK marketplace – wood-aged beer.
Which is why I was at Thornbridge Hall in Derbyshire last Monday for the Zythographers’ Union’s latest seminar, tasting different styles of beers aged in different ways in different types of cask, and listening to Garrett Oliver of the Brooklyn Brewery, John Keeling of Fuller’s in London and Dougal Sharp himself talk about their wood-aged beer experiments and experiences.