I am using a small coffee grinder to grind up my cannabis. After I use it for a while I find that a thick layer of…tricomes? builds up in the bottom of the grinder. It’s extremely sticky. What exactly is this stuff and what do I do with it?
What you are seeing is kief and kief is cannabis gold!
What is kief? You were correct when you surmised trichomes. Kief is the resinous trichomes from the cannabis plant, without a whole lot of plant material attached. The trichomes contain most of the plant’s medicinal properties, meaning the cannabinoids and terpenes.
What can you do with kief?
You can even press kief into hash.
Using a coffee grinder, you will see a lot of build up very quickly. But even hand grinders will accumulate build-ups of kief. In fact, quality marijuana grinders come with built in kief catcher screens (AKA “pollen catchers”).
I use kief in many of my recipes. The article at this link will teach you more about how to cook with kief and hash.
You may find you want more kief than your grinder and smoking habits provide. If so, it is super simple to make. This video tutorial on making dry ice kief shows how.
On a side note, you mentioned using a coffee grinder to grind your weed. If you are planning to use the cannabis for cooking, I generally do NOT recommend fine grinding with a coffee grinder. To learn why not, see this article and video that talks about a better option.