This article featured in the August edition of Australian Bartender magazine.
By Philip Duff
We discovered aging by accident. Long before Coffey patented/nicked the idea for a continuous still, our forefathers found a way to make rough liquor taste better – barrels. Barrels were exclusively what you used to store and transport spirits. They smoothed out harsh liquor and provided a place to store distilled grain.
Oak is great barrel-wood and it’s specified in numerous laws as being the wood for aging. In Appreciating Whisky, Phillip Hills points out that a common English view around the time of the American War of Independence was to simply write the colony off as a failed financial venture. If it hadn’t been for America’s a vast supply of oak (then used Royal Navy shipbuilding) the colonials might just have been cut free.
US law specifies that oak whiskey barrels be used only once for producing bourbon, thus ex-bourbon barrels are the most common around going for $100AUD or so (ex-cognac barrel may cost ten times more). American oak (Quercus alba) is harder to penetrate than European oak (Quercus robur) which is the stuff used in Spain and France’s famous Limousin and Troncais oak.
Before filling the barrel, what you do to it can have a profound impact on the resulting spirit. Char the inside, as with bourbon, and you’ll change what it is. You’ll add a layer of carbon (an excellent filter that smooths out rough liquor) and you change the chemistry of the wood. Phenols decrease when you char, as do tannins, while concentrations of aldehydes and acids rise.
Once it’s filled we wait, and extremes of temperature are probably best avoided. As the barrel ‘breathes’ the spirit will be influenced by the environment hence Islay whiskies have a tang of salt and brine and Linie Aquavit has all sorts of exotic seafaring scents (it crosses the equator twice in barrels before being bottled, echoing it’s original use as ballast, on trading ships).
While aging, colour leaches into the liquid from the barrel, but not as much as you might think. Ireland’s Cooley Distillery master blender/distiller Noel Sweeney told me categorically that you cannot get a dark whiskey through aging in bourbon barrels. You have to colour it. No harm there – spirit caramel is used, which does not affect taste unless you really go overboard.
“But what of aged cocktails? It’s not a new idea. 1800s bartenders made bottled cocktails for their guests to enjoy while travelling.” Philip Duff
Flavour transfers from the wood to the liquid too – lots of flavour. Phenols are a woody plant’s last line of defence, pungent chemicals deep in the heartwood designed to discourage burrowing insects. Phenols include eugenol (cloves) anethol (anise), cinnamaldehyde (cassia/cinnamon) and their superstar in the whiskey world, vanillin, which comes from the lignin in the wood. When we taste vanilla we automatically think of the food or drink we are ingesting as being sweeter, because we almost always taste vanilla in conjunction with a sweet food or drink, although vanilla itself is not sweet.
And what of the famous barrel ‘finishes’? You cannot add flavouring to most whiskies and still sell them as whisky, but you can age the whiskey for a short time in a barrel previously used for something else like Sherry or Port. In Scotch, using casks other than the traditional ex-bourbon or ex-Sherry was first popularised by Glenmorangie in 1995. Now it’s a bit of a game, and lots of people in the whisk(e)y industry regard the explosion of finishes in the the way most cocktailians regard ‘new’ flavoured vodkas.
New Trend – Old Fasioned
What of aged cocktails? It’s not a new idea. 1800s bartenders made bottled cocktails for their guests to enjoy while travelling. In the 1900s, drinks firms marketed bottled cocktails large-scale.
Arguably, RTDs are bottled cocktails. The difference between a 6-week old Negroni and a Watermelon Breezer is that the barrel-aged cocktails aim to improve the flavour of the liquid – RTDs aim to taste exactly like a fresh-made cocktail even though they are bottled.
You can get a five or 10 litre barrel for a steal. Age five liters of, say, Negroni in one, and you can make 50 barrel-aged Negronis (exluding ‘Bartenders’ Share’). Ask a touch more for your aged cocktail and you’ll recoup your barrel cost in no time. You should also get some media, AND you can serve the cocktails much more quickly. Cool!