Hash, is the product created when marijuana flowers are sieved through a screen, also known as “dry sifting,” and processed with heat and pressure. Dry Sifting is a process used to separate the resin glands, called trichomes, from other plant matter. The extracted trichomes, with a powdery appearance, are commonly known as kief. Most take the process a step further and add heat and compression to the kief to form blocks of hashish.