Bubble hash, named for the way it bubbles when smoked, refers to a specific type of hash made with ice water. To make bubble hash, cannabis flower is added to bags of ice water (called “bubble bags”) and agitated, which freezes and then breaks the resin glands from the flower. These broken resin glands, which contain essential compounds like THC and CBD, move through a series of screens while the plant material is left behind, forming bubble hash.