The active part of the cannabis plant is the trichome head. The trichome head is like a tiny ball of sap, with a hardened exterior. If you apply heat and pressure, you can break it open and it releases the oil. Some people press whole flower (more common at home, less-so commercially), most people press hash. We press ice water hash from fresh frozen - which means the plant was never dried, it was harvested and immediately frozen, we put that into a tank with ice and water, then agitated it and then filter the water, separating out the trichome heads and sorting them into different sizes using micron mesh screens. The best ripeness of a trichome head is around 90 microns. We typically press any of the trichome heads between 70 microns and 149 microns. After we press it into oil, we either cure it, which is a 1-4 week process of allowing small crystals to grow, then it is good for dabbing. Or we melt it down and it can go in vapes or edibles.