The biggest decision facing most cocktail lovers used to be whether they would prefer their tipple shaken or stirred. Now they can also choose how old they would like it to be, thanks to an unusual but increasing vogue for cocktails that have been aged in oak barrels.
The drinks are appearing in bars across the UK. According to cocktail experts, contact with the oak, and the natural oxidisation that comes as the drinks age, enhances and softens the flavours. Other factors likely to affect the taste of a vintage cocktail include what the barrel was previously used for and how charred it is inside.
Bramble Bar and Lounge in Edinburgh is struggling to keep up with demand since launching a "Scottish Manhattan", aged for six weeks in Glenmorangie whisky barrels, two months ago. Hyde & Co in Bristol is poised to offer its next vintage of barrel-aged Hanky Panky, while London venues serving barrel-aged cocktails include the Donovan Bar at Brown's Hotel and Artesian at the Langham.
The idea of serving cocktails from barrels is actually centuries old. Its revival coincides with a renewed interest in classic cocktails and the launch of historically influenced bars. The Victorian-themed Worship Street Whistling Shop in Shoreditch, east London, opened in April and serves six barrel-aged drinks. Tristan Stephenson, co-founder of the cocktail consultancy Fluid Movement, which owns the bar, says that cask ageing is a process of "trial and error".
"Just because you stick a cocktail in a barrel doesn't mean it's going to get better," he warns. "It has to taste good."
VOC, a modern interpretation of a 17th-century punch house, near King's Cross in central London, has served drinks aged in casks above the bar since opening in May. Alex Palumbo, the bar's manager, says they were partly inspired by the grog once drunk in large quantities by sailors, made from rum, lime, water and sugar.
Barrel-ageing cocktails took off in the US after a well-known cocktail maker, Jeffrey Morgenthaler, experimented with the practice in Portland, Oregon. But the concept of cocktail ageing was in fact born in the UK. Mr Morgenthaler had himself been inspired by a visit two years ago to 69 Colebrooke Row, Islington, a London bar run by "mixologist" Tony Conigliaro, who pioneered the use of glass bottles to age his creations.
Not every cocktail is a good candidate for the process. Marcis Dzelzainis, the bar's operations manager, has heard of people maturing pina coladas but believes that it is "dangerous" to age drinks containing fermentable ingredients, such as fruit juice or cream.
So, while the idea of mature cocktails may not sound appealing, having nobly tasted some in the line of duty, I am surprised to say that you really can taste the difference.
Perched on a bar stool at VOC, underneath a row of casks and in front of an intriguing display of everything from an antique Bunsen burner to rows of wax-sealed bottles, I discovered that not only does the aged Yellow Martini look different from the fresh version – after three weeks in a barrel it has a champagne hue – but it also has a much smoother, cleaner flavour.
At 69 Colebrooke Row – on a different night, to save my liver – I found a two-year-old Manhattan much gentler on the palate and more enjoyable than the sharper, fresh drink. Make mine a vintage cocktail.