IPA stands for "India Pale Ale." These were beers that were crafted in England, and shipped from England to India, during the Occupation.
Hops are a preservative, and the flavor diminishes over time. Excessive hops were added to IPAs in order to preserve them during this long transcontinental journey, and when the beer reached its final destination, the bitter hop character would diminish and mellow, resulting in a pleasant drinking experience similar to what you'd have in the home country of England, from a beer that was freshly brewed and had far less bitter hops added because it didn't have to make the trek to India.
I've enjoyed many English IPAs over the years-- after they've been properly aged and rested, as they would have if they'd been shipped to India.
But Americans, being who and what we are, decided we needed to brew these beers with excessive hops, and then drink them immediately. The resulting bitterness was never intended for consumption, but of course Americans did American things, and here we are. For almost two decades, it completely ruined the American craft beer palate, and we're only in recent years emerging from that and finding breweries willing to brew better nuanced and more flavorful beers, instead of the standard too-bitter over-hopped American IPAs. But even so, the West Coast IPA still dominates the American craft beer market.
