Enlarge / Regional differences in the aromatic compounds found in hop varieties can significantly affect the taste of craft beers. (credit: DEA/G. Wright/Getty Images)
If you’re a fan of craft beer with a strong, hoppy flavor, heed the science that says to store your beer in a cool place and drink it within three months or so, lest it lose that rich aroma. That’s one of the key takeaways from a new study by German scientists published in the journal Brewing Science.
All beer contains hops, a key flavoring agent that also imparts useful antimicrobial properties with its rich aroma. (Without them, beer spoils quickly.) To make beer, brewers mash and steep grain in hot water, which converts all that starch into sugars. This is traditionally the stage where hops are added to the liquid extract (wort) and boiled to give the beer that hint of bitterness. That turns some of the resins (alpha acids) in the hops into iso-alpha acids, producing a bitter taste. Yeast is then added to trigger fermentation, turning the sugars into alcohol.
Add too many hops, however, and the beer will be so bitter as to be undrinkable. So in recent years, many craft brewers have started using dry-hopping as a way to put more hops in beer without getting excessive bitterness. Hops are added during or after the fermentation stage, after the wort has cooled. There is no isomerization of the alpha acids, so you get all that aromatic hoppy flavor without too much bitterness. Brewers can use as much as 20 times the usual amount of hops if they’re dry-hopping. (Just beware of “hop creep,” which can cause such bottled beers to explode.)