On August 13th of this year, Other Half Brewing teamed up with The Veil Brewing to release one of the strangest, most seemingly paradoxical beers ever made. By now, both the Brooklyn and Virginia breweries are some of the most famed IPA makers in the country, proponents of the hazy Northeast-style “juice bombs” that are de rigeur these days. And on that Saturday in August, geeks were champing at the bit to acquire cans of their latest collaboration, Topical Depression. Now for the kicker: the IPA had a reported zero IBUs.

Standing for International Bitterness Units, IBUs were at one point the purest measure of hoppiness in a beer. If Scoville Units told you how scorching a hot sauce was, IBUs told you how hoppy an IPA was. Then, over the last few years, as breweries started relying on hop varietals that were fruity, not bitter—like the Galaxy and Citra used in Topical Depression—IBU numbers, and perceived bitterness, began dropping. Likewise, dry-hopping became a crucial weapon in an IPA brewer’s arsenal, adding an intense aroma and flavor, but not raising IBUs one lick. Thus, an unheard of zero IBU IPA suddenly became not just possible, but sought-after.

Still, I long for the days when IPAs were actually bitter, not just alcoholic fruit juice. That was the case back around the turn of the decade, when “hop bombs” were arising with punishing names like Palate Wrecker and Tongue Buckler. The average IPA then used to register around 70-100 IBUs, with most folks believing anything over 100 to be imperceptible and just a theoretical measurement. But that didn't stop an array of brewers, from Denmark to Delaware, from battling it out to hold the crown as makers of "the hoppiest beer ever." 

Here, we take a look at the 10 hoppiest beers of all time, as defined by IBUs—that brewing statistic that has almost become obsolete.