‘There was a thing here that I never saw. I don’t think you’ve ever seen it either. There were Americans came here and they put whiskey in the beer.’ ‘No,’ I said. ‘Oui. My God, yes, that’s true.’
Wine of Wyoming, Ernest Hemingway, 1933
Although several important British beer styles, such as porter and India Pale Ale, required ageing in wooden casks or vats, British brewers made big efforts, until very recently, not to let any flavour from the wood get into the beer. Unlike wine makers or distillers, brewers wanted their drink untainted with tannic or vanilla flavours from the oak used for making storage vessels – wood flavours were fine in chardonnay, or scotch, but not in stout or old ale.
Today, however, beers aged to deliberately take flavour from the wood are defining a new and exciting style of beer in Britain. But in past times oak for casks, vats and brewing vessels was sourced from places such as Russia and Poland that were known for growing fine-grained 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. As aluminium and steel casks began to replace wooden ones, a protesting group of British consumers formed the Society for the Preservation of Beers from the Wood in 1963, but their objections were more to do with disliking the pressurised, pasteurised beer that frequently came in metal casks, rather than the loss of any real benefits obtainable from wooden ones.
About the only desirable characteristic brewers did want from storing in oak vessels was that brought out by Brettanomyces yeast infection. Brett, a different family from the usual Saccharomyces brewing yeasts, gives an earthy, funky aroma to beers and old wooden vessels are often infected with it. Brett flavours develop after three or four months when the standard Saccharomyces yeast has done as much as it can to ferment the sugars in the beer and the Brettanomyces yeast sneaks up and tackles what sugars are left. They are regarded as essential, as a background, in aged brews such as Guinness Foreign Extra Stout, Belgian lambic and the old-style (and now almost vanished) English stock beers, which were kept for months to mature and from which the Danish biochemist Niels Hjelte Claussen first isolated the yeast in the first decade of the twentieth century.
In wine-making, Brett flavours are regarded as a fault, but beer brewers are (again) beginning deliberately to infect some of their beers with Brettanomyces. The bottle-conditioned London Porter from the Meantime brewery in Greenwich, for example, has Brett yeast sourced from the United States added to it during fermentation.
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 for filling the casks that he and Grant’s felt would give a good foundation when those casks were subsequently used for maturing whisky in. The beer was always meant to be thrown away once it had been in the casks long enough for the wood to absorb beer flavours that could then be absorbed by the whisky. But workers at Grant’s distillery sampled the beer before it was dumped 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 in lemonade bottles.
When he heard about this, Sharp tried putting the oaky 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 (Innis and Gunn are names in the Sharp family tree) has been so successful subsequently it has effectively launched a completely new category in the UK marketplace, the first new beer style of the twenty-first century: wood-aged beer. Innis & Gunn has had to learn new tricks with this new category of beer. Each cask produces a slightly different flavour, for example, so that to achieve consistency the beer, after it has been aged for thirty days in the casks, is vatted for another forty-seven days to let the flavours from the different casks marry and mature. Then, immediately after the beer is bottled, the oaky flavours disappear, subdued by the violence of the bottling process, and do not reappear for a month, so every bottle has to be kept at least four weeks before it is released for sale, in order for the proper taste to return.
Subsequently, Innis & Gunn has brought out a number of different versions of cask-aged beer, including one aged sixty days in American oak barrels and then forty-seven days in barrels that had previously contained rum. Again, whisky distillers had been ageing their spirit in ‘second-hand’ casks for many years, but this was a new development for brewers.
Other small Scots brewers have now brought out beers that have been aged in whisky casks, including Harviestoun, with a brew called Ola Dubh, Gaelic for ‘black oil’, which is its Engine Oil stout aged in casks formerly used to mature Highland Park single-malt whisky from Orkney. The Brew Dog brewery in Fraserburgh, near Aberdeen, established in March 2007, has been putting its strong Paradox stout in casks that had previously contained whisky from, among other places, Islay distillers such as Caol Ila and Bowmore, with each batch using casks sourced from different distilleries.
As well as flavours, the beer also pulls out alcohol from the casks that had soaked into the staves from the whisky, which is why, for example, Paradox starts out at 8.5 per cent abv and rises to 11 per cent after its time in wood formerly used to mature the whisky. In the nineteenth century, when pub landlords bought whisky by the cask for subsequent retail in their pub, they would extract this alcohol from empty barrels by filling them with a small quantity of water and rolling the casks around the pub yard. This practice, known as ‘grogging’, has been illegal in Britain since 1898, since the authorities decided that the alcohol liberated from the wooden staves of the cask had not had tax paid on it. Some brewers trying to make beers matured in whisky casks have hit difficulties with Her Majesty’s Revenue and Customs, which has told them that because alcohol comes out of the wood into the beer, what they are doing is grogging, and therefore illegal.
One company that had been experimenting with maturing some of its beers in ex-whisky casks was Fuller, Smith & Turner of Chiswick, in London. With Golden Pride in Glenmorangie casks, a mixture of secondary fermentation and leaching out of whisky that had soaked into the wood inside the cask saw the abv of the beer rise from 8.5 per cent to a serious 12.5 per cent; However, with the local revenue and customs people telling Fullers it would be illegal to sell the beer because of the century-old law against grogging, this particular version never reached the buying public. The same was true of Vintage Ale (the version of Golden Pride normally sent out bottle-conditioned) matured in ex-Jim Beam bourbon casks, where the beer saw a similar rise in abv to 11.5 per cent.
However, the brewery eventually found a compromise with the authorities. If it released the whisky cask-matured beer at a lower abv than the beer was when it originally went into the casks – water it down, in other words – then it could put it on sale. The company was thus able to put a version of Golden Pride aged in whisky casks and then reduced in strength to 7.5 per cent abv on sale in the summer of 2008.
While this is likely to give a big fillip to the idea of wood-aged beers in the UK, in the United States brewers have adopted the practice with enormous enthusiasm. A survey by Garrett Oliver, brewmaster at the Brooklyn brewery in New York, of fellow American brewers in 2007 found some 200 or so of the 1,500 craft brewers in the United States made a wood-aged beer of some sort, with a small handful making all-Brettanomyces beers; Russian River in California, for example, and its fellow Californian Pizza Port, with Mo’Betta Bretta The range of beers they had aged in oak deliberately to get oak flavours included imperial stout, barley wine, Belgian abbey-style ale, brown ale, red ale, the Scots strong pale ale style Wee Heavy, cherry stout and Belgian golden ale.
Barrels used were mostly Bourbon (by law, Bourbon distillers can only mature their spirit in fresh, unused barrels and thus have a lot of barrels to get rid of once each batch of Bourbon is old enough for bottling), but also red wine (in particular Pinot Noir) and white wine.
Some brewers steamed the casks before filling them to try to sterilise them, others flushed them with carbon dioxide or sulphur dioxide, but most used them as they came, generally (if they were Bourbon barrels) with a couple of pints of whiskey still inside to help keep the staves moist.
No one method seemed to make much difference to how the beer turned out after its time in the cask, though obviously those beers matured in casks that had Bourbon still in them when filled had more Bourbon character in the final result.
American brewers now hold beer festivals solely dedicated to wood-aged beers and Mr Oliver, whose own brewery made a 10 per cent Bourbon-cask-aged stout called ‘Black Ops’, declared at a seminar at Thornbridge Hall, Derbyshire in 2007 on wood-aged beers, that wood-ageing has become another flavour tool for modern brewers – not a traditional tool at all, but now an accepted part of the ‘creative toolkit’. While deliberate wood ageing had previously been left to the wine makers and distillers, Mr Oliver said they were now being challenged: ‘We [brewers] will use barrels in a more interesting way that any of the other drinks disciplines.’