In a city frequently battered by the Gulf of Mexico’s windy progeny, one could be forgiven for thinking that a drink called ‘the Hurricane’ might be a bit tasteless. But it is in fact, a very tasty rum-based cocktail, and the classic drink of New Orleans, home of the ACS spring conference 2013.

Philip tests a hurricane cocktail at the ACS New Orleans meeting. For science!

The Hurricane was invented, so the story goes, during the second world war. Whisky supplies were scarce and spirits distributors took advantage of this to shift the more plentiful, but less popular, rum by packaging a hefty order of the spirit with any whisky they sold to bars. Forced to buy large quantities of rum, barman Pat O’Brien began bundling generous helpings of it with lime juice and passion fruit, which went down a storm with the local sailors. Incidentally, the drink is not actually named for those occasional city-levelling ventose visitations, but for the glass in which it is served, which resembles the glass casing of a hurricane lamp, designed to safeguard the kerosene flame against the blustery gusts that might snuff it out.

70 years later, as several thousand chemists beat a path to Bourbon Street, the odds that one of them might get analytical on the city’s cultural icon seem pretty good. And, indeed, the conference boasts a whole session dedicated to booze: ‘Chemistry of the bar’, in which the first order of business was flavour chemist Neil Da Costa’s GC-MS breakdown of the hurricane.

The recipe calls for about 120cm³ rum so, as you might expect, ethanol is fairly dominant. But there are also contributions from the oak barrels in which the rum is aged: some sweet vanillin; guaiacol bringing burnt, smoky flavours; syringaldehyde, lending a floral spiciness; and even a little coconut from coniferyl alcohol. A large limonene and citral spike courtesy of the lime juice freshens up the profile. The modern recipe also includes plenty of the rum precursor and also grenadine, whose role, it turns out, is mostly cosmetic – the tannins it contains giving the hurricane its distinctive red colouring. The whole thing is served over ice, which acts to refresh the consumer and, as Da Costa points out, keeps the delicate fruit juice aldehydes from oxidising to acids.

‘What’s “n” in this experiment?’ Laura wonders

Da Costa’s analysis certainly seems thorough but as dedicated science journalists, we are bound by codes of scientific conduct and our journalistic integrity to determine the facts for ourselves. Thus, Laura and I have put our livers on the line to see if we can duplicate (perhaps even triplicate) the findings. Applying our own sophisticated sensing equipment to the task, we conducted an independent analysis of the hurricane and I’m pleased to confirm that our results are largely in support of Da Costa’s. Our instruments struggled to detect the intricacies of the rum profile amid the citrus and sugar, but there was certainly a large positive response for ethanol.

The Big Easy’s other classic cocktail is the Sazerac – a whisky-based drink carrying what was once the defining element of the cocktail – bitters. These ethanolic infusions of plant roots, bark and so on are packed with terpenes that give aromatic, floral tones. Originally sold as patent medicines, they found their way into drinks in the 19th century, when the Royal Navy added them to gin (creating pink gin). Analytical chemist Arielle Johnson has been taking a closer look at bitters to identify the compounds they contain and the flavours they deliver. Having fallen out of favour for many years, bitters are enjoying a comeback in the craft cocktail market, so Johnson is sharing her work with local barmen and women to develop new recipes. We may soon see the first products in the nascent field of rational cocktail design. Cheers!

Philip Robinson

                  

Source:
http://prospect.rsc.org/blogs/cw/2013/04/11/chemistry-of-a-hurricane/