Now that beer experimentation seems to be shifting from Belgian styles to hoppy ales, the IBU—international bitterness unit—has assumed a new importance. IBUs primarily measure iso-alpha acids, the chief bittering compound in hops. The scale was devised in the 1950s to help brewers keep their recipes consistent from batch to batch.
In American-style lagers, the IBU level is typically 12 or below, while a hoppy Pilsener measures 20 to 30 IBUs and will have a pronounced bitter character. An IPA, at 50 to 60 IBUs, should smack you in the face with hops.
Today, IBU levels are often trumpeted on beer labels, brewery websites and supermarket placards, a way of bragging that my beer is bigger than yours. The measurement does help consumers compare one style with another. And as a result of the public’s craving for ever-hoppier beers, craft breweries are taking IBUs into the stratosphere.
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