Top-shelf whiskeys, rums and brandies owe much of their flavor to the length of time they spend aging in wooden barrels. But a group of researchers from Spain recently experimented with a scientific shortcut to the aging process and it involved blasting brandy with ultrasonic waves.
The chemistry responsible for aging alcohol is complex and difficult to speed up. Distillers use words like “extraction,” “esoterification” and “oxidation” to describe the intricate processes that result in high-end spirits. In a nutshell, it goes something like this: as immature booze ages, phenols and acids in the liquor latch onto alcohol to form molecules called esters, which contain much of the aroma and flavor associated with aged spirits. Meanwhile, as the wood from the barrel breaks down, a cocktail of tannins, pigments and sugars are released into the distillate. Essentially, the more time afforded for these processes to take place, the smoother and tastier the booze.
Research has shown that adding ultrasonic waves into the mix can be a little like hitting the fast-forward button. In a recent study, scientists pumped immature brandy through a glass tube filled with American oak chips. As the liquor flowed through the tube it was blasted with ultrasonic waves to forcefully infuse woody flavors into the liquid.
According to the researchers, their tipple time-machine is capable of churning out a brandy in three days that has the characteristics of one that has been aged for two years. The ultrasonic-aged brandies were chemically analyzed and taste tested. “They tasted surprisingly well, with good fruity and sweet flavors and a high aromatic intensity,” says study co-author Valme García, a professor at the University of Cádiz in Spain.
So does this mean that we’ve cracked the code for rapidly aging booze? Well, not really. “The use of ultrasound to mature spirits is not a new idea,” explains Bryan Davis of Lost Spirits Distillery, a company known for utilizing innovative tech to produce some of the most unique booze in the world. While this may be the first time the technique has been used on brandy, the process was actually patented back in 1934. Waiting for spirits to age traditionally can be costly, so some distillers, like South Carolina’s Terresentia, have turned to technology to help get their products from barrel to shelf in a hurry.
“Our process is not intended to compete with extensively aged whiskies desired by connoisseurs,” explains Terresentia CEO Earl Hewlette. “But rather [it is] a cost-effective alternative to the four and five year-old bourbons that comprise 85% of the market.”
Ultrasonic aging can help conjure up a semi-decent bottle of booze, but “the products made using the technology generally fall short of offering … anything close to a fully mature 15-20 year old spirit,” argues Davis, who believes that the technique is too limiting.
We’re also not entirely sure exactly how ultrasonic waves improve the aging process.
“It is possible the vibration produced by the waves is rattling some of the lignin and hemicellulose polymers around in the wood and causing them to partly degrade into the spirit,” Davis suggests.
In addition to shaking things up, the waves can also create a reaction called cavitation, in which mini, super-heated bubbles are formed that increase the temperature of the distillate.
The idea of using heat to speed up maturation has been around for over a century and has yielded some positive results. However, heat will only get you part of the way to a world-class whiskey or brandy. There are a host of other compounds responsible for maturation that are not mentioned in the new study.
Attempts to master the complex art of aging liquor has led distillers to meddle with all manner of creative techniques, and they’ve been doing it for a long time. The reality is that a silver-bullet solution for speedy maturation doesn’t really exist. Ultrasound is useful, but alone it’s not enough. Distillers are still on the hunt for the elusive golden recipe of scientific trickery and creative conjuring that can produce a perfectly aged spirit without the lengthy wait. Some claim that they’ve already found it, others are not convinced. In the meantime, savor every sip of that well-aged bourbon— the next batch might take a while.