Micron grade refers to the fineness of a mesh screen, also called a micron screen, that is used to make ice water hash, aka bubble hash. A variety of micron-grade mesh screens are used to filter the different sizes of trichome heads from contaminated plant matter. Itâ€™s all about the size of the heads on the trichomes, which can vary like fruit on a tree.
Common micron-grade screens used for hash making are 73, 90, and 140 microns for high-quality hash. With different micron screens, you can filter the hash for the best possible separation of trichomes for full melts with less contaminated plant matter.