Ice-water hash (also “bubble hash” or “ice hash”) is the foundational solventless extraction. Fresh-frozen or fresh-cured flower is agitated in a vessel of ice water, which causes the brittle trichome heads to break off the plant material. The slurry is then filtered through a series of micron screens (typically 220μ down to 25μ), and the captured trichome heads are dried — historically by air, now by freeze-dry for terpene preservation. Quality is graded on a 1–6 star scale: 6-star bubble hash will fully melt on a hot nail with no residue, indicating a high purity of trichome heads and minimal plant matter contamination.
Updated · LimeLine editorial · MN cannabis topic