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How do you define an imperial or double IPA?

In simplest terms, a double or imperial IPA — they’re actually the same thing — is an IPA kicked up a notch. The Brewer’s Association defines an Imperial IPA as an IPA with color that is straw to medium amber, 6.0%-8.4% alcohol, with hop aromas and flavors that are very high, but not aggressively bitter.

Among brewers the general consensus is that a double IPA is an IPA with amplified aromas, flavors, and alcohol. The hops are more aggressive both in aroma and flavor, and the alcohol is typically above 7 percent, though this is not a formal rule, since the BA says it can go as low as 6%. So calling an IPA an imperial or a double is really up to the discretion of the brewer.

This style of IPA is still pretty young, too. It’s believed to have been invented by Vinnie Cilurzo, founder of Russian River Brewing, in 1994. Since then, the style has been adapted to meet the needs of whoever is brewing the beer. So if you order an imperial or double IPA the next time you’re out, just remember it’s probably hoppier and more alcoholic than the other IPAs you might be used to.