(Credit: FXQuadro/shutterstock) Keep those craft beers cold and don’t hang on to them for too long. That's the advice from researchers at the Technical University of Munich’s Leibniz-Institute for Food Systems Biology. Scientists there found that cold-stored craft beers lost more than one-third of an important hop aroma after just three months. The beer lost even more flavor when kept at room temperature. These are generally beers created with a method called “dry-hopping,” where hops is added to young beer late in the brewing process. Different hop varieties have different compounds important for their flavor. And for this particular study, the scientists looked at an odorous compound with an unwieldy name — 4-mercapto-4-methylpentan-2-one — because it plays a big part in the flavor profile that comes from popular hop varieties like Citra, Eureka, Simcoe and Apollo. These hops are commonly found in what beer fans think of as "juicy" or New England IPAs. Beer experts have described the hop-derived compound's profile as being “reminiscent of black currant berries.” So scientists measured the compound's concentration over a 6-month period, in both filtered and unfiltered craft beers stored at around 41 degrees Fahrenheit and 68 degrees Fahrenheit. By the end of the study, the aroma compound had decreased to just 59 percent of its original concentration in cold filtered beer, or 67 percent in unfiltered. The room temperature bottles fared even worse, decreasing to 30 and 40 percent respectively. So if you’re a craft beer lover, don’t hoard those brews, drink ‘em cold and fast — science says so. The results were published in the journal

BrewingScience.