What Makes an IPA an IPA?

IPA has become the single most dominant craft beer style in the US, and understanding its actual origin explains why heavy hopping specifically defines the category.

The Historical Origin

IPA's name references beer brewed in England and shipped to British colonial India in the 18th and 19th centuries — a long sea voyage that put real strain on beer's stability. Brewers discovered that adding significantly more hops (which have natural preservative properties, beyond their bitterness and aroma contribution) helped the beer survive the journey in better condition.

Why Hops Are IPA's Defining Feature

That historical preservation need is exactly why heavy hopping remains IPA's core defining characteristic today, even though modern shipping and refrigeration have eliminated the original practical necessity — the hop-forward character became the style's identity rather than simply a means to an end.

What Hops Actually Contribute

Beyond bitterness, hops contribute a wide range of aroma and flavor characteristics depending on variety — citrus, pine, tropical fruit, floral, and earthy notes are all achievable through different hop selections, which is why IPAs can taste so different from each other despite sharing the same core "heavily hopped" identity.

Bitterness Measurement: IBU

IPA's bitterness is often measured and marketed using IBU (International Bitterness Units), giving drinkers a rough numerical sense of how bitter a specific IPA will be, though this number doesn't capture aroma or flavor complexity — two IPAs with similar IBU can still taste dramatically different depending on hop variety and brewing technique.

IPA's Explosion Into Substyles

The core IPA concept has splintered into numerous substyles over recent decades — West Coast IPA, New England/Hazy IPA, Double/Imperial IPA, session IPA, and more — each interpreting the "heavily hopped" foundation in a genuinely different direction.

Why IPA Became Craft Beer's Signature Style

IPA's flexibility — the enormous range of possible flavor profiles achievable through different hop selections and brewing techniques — has made it an ideal canvas for craft brewers to showcase creativity and distinct house styles, a major reason it's become the most prevalent and highest-profile style within American craft brewing specifically.