Thursday, August 1 marks the third annual IPA Day, celebrating the most popular craft beer style on the planet. But why, you might ask, do IPAs warrant their own day of celebration?

The India Pale Ale beer style evolved in the 18th century to slake the thirst of Englishmen living in India. It was seen at the time as a literal lifesaver. Between contracting diseases and binging on the local, palm-based rotgut known as Arak, the average life expectancy for a European living in India was three years. To satisfy the need for a safer adult beverage, Hodgson Brewery in East London adapted the existing pale ale style to include more alcohol and hops. This enabled the beer to better survive the six month overseas trip from England to India. Porters could also survive the trip, but IPAs were refreshing and light, and India is hot. As a result, IPAs became immensely popular.

Interest in the style waned over the years as brewers and consumers turned to an arguably more refreshing and lighter beer style: lager. The current IPA renaissance started in the 1980s as West Coast craft brewers and their customers, bored with the increasingly industrial sameness of lagers, looked for a beer style that would best showcase their local citrusy and resiny hop varieties. IPAs fit the bill perfectly; there is simply no better beer style for creating the hoppy flavorbombs we’ve grown to love.

What started as a 1980s regional obsession has spread to the rest of the US and beyond. As Sayre Piotrkowski, the beer director at St. Vincent Tavern, recently remarked, “It’s always worth remembering that West Coast IPAs really did change the world. When you travel abroad now, the reverberations of the iconic West Coast hoppy beers are apparent everywhere.”

While you can find IPAs on tap in nearly every San Francisco bar, these two local establishments will be hosting events to mark the day:

• Rosamunde Grill at 2832 Mission Street is having an IPA tap taker, which will include a few exotic IPAs in addition to the usual suspects.
• 21st Amendment at 563 2nd Street will feature specials on their Brew Free or Die IPA and Back in Black IPA all day. They will also tap Back in Black OG, an experimental version of their popular Black IPA.

As part of the IPA Day celebration, social media aficionados are encouraged to share photos, videos, blog posts, and tasting notes by using the #IPAday hashtag. You can follow the day’s tweets by searching #IPAday on Twitter.