Bubble hash refers to a specific type of hash made with a process involving ice water. Like traditional hash, bubble hash is a solid concentration of cannabis resin glands, or trichomes. It can range in color from light blonde to dark brown. Bubble hash gets its name from its tendency to bubble when brought under a lighter’s flame.

“Full melt” is considered the highest quality of bubble hash. The ultra-refined full melt tends to largely bubble away when smoked or dabbed, leaving little material behind. You may also see hash rated on a scale of one to six, with six-star hash being the most refined and desirable. These highest quality hashes are made using extremely fine mesh sieves that prevent plant material from passing through—only the small trichome heads.