While not quite up to the standards of a truly-aged brandy, the ultrasonic spirits were still well received. Here’s Charles Q. Choi, reporting for Discover:
“Obtaining, in three days, a spirit with characteristics near to two-years-aged brandies was something really unexpected for us,” says study co-author Valme García, a professor at the University of Cádiz in Spain.
Eight trained judges, including some of the researchers, deemed the resulting spirits nearly as good as traditional brandies. “They tasted surprisingly well, with good fruity and sweet flavors and a high aromatic intensity,” García said.
The best brandy produced in this experiment was stiff—130 proof, or 65% alcohol—and run past a large number of oak chips at room temperature with a bit of aeration.
The accelerated aging is brought about thanks to ultrasound-induced cavitation in the oak chips, where small bubbles formed by the sound waves “explosively collapse,” blasting the wood’s tissues and releasing compounds that add distinctive flavors to the liquor. Booze experts call these “congeners.”
While the liquor produced by the accelerated aging process can’t legally be called brandy in Europe since regulations require that the spirit be aged in oak casks, Gargía pointed out that the technique could be used to help distillers accelerate their development process. Want to know how a new cooper’s casks will affect the flavor? Add ultrasound. What about a different species of wood? Again, ultrasound could help.
Beyond that, more adventurous distillers may gin up entirely new alcoholic beverages with unusual flavors. For García, wine is next on the list.
Ultrasound appears to dramatically accelerate the aging process.