It’s a different kind of Ice Bucket challenge. Dunkin’ Donuts has the nation’s java junkies going gaga after trialing a brand new iced “coffee bucket” that holds a whopping third of a gallon of java.

Cold coffee is booming in the U.S. In 2023, Americans spent about $17.7 billion on out-of-home cold coffee including iced coffee, cold brew and frozen coffee drinks. That is more than double the $8.5 ...