Cannabis rosin is created by placing ice, water, and fresh cannabis flower into a vessel. After agitating the mixture, the trichomes of the cannabis plant get suspended in the water. The water is drained through a series of filters trying to only catch the fully intact gland heads of the trichrome, while leaving as much waste and bio-contaminants behind as possible. This is then dried using either forced air or a freeze-drying process. After it is done drying you are left with a pure substance known as ice water hash or “bubble” hash.