Herbal (read that as plant material) extraction techniques are nothing new, it's been done for many centuries. There are basic decoctions, like making tea or coffee with heated water; and basic infusions (chop up the material and soak it in water, alcohol, or in our specific example often PG, with no or little heat involved) my understanding is that there are other more modern (don't necessarilly read that as "better") twists on these ancient methods that involve other carriers. I've heard of CO2 and Butane and I'd expext that there are other methods as well, but I'm not at all well versed in this area. Mr. Mann may have more to add here. Separation processes can be as simple as filtering through various media (like a coffee filter) to settling techniques, to added ingredients that aid in separation. But keep in mind that separation removes more organic plant material (suspended particulates) and it changes the end product (this is why so many of our favorite vapes are also atty cloggers, removing more of the original plant material also removes more of the original character of the plant). Again, nothing even remotely new in this regard. The end result is a suspension, where the extracted product (and any other desired added ingredients/flavorings) are mixed with VG/PG to obtain the desired "vapable" result. The process is not rocket science, it's the art of the taste that is the "secret" ingredient. Like a skilled chef, or a great band, or any other art, the processes are well established, but the end result is very much more of an artistitic endeavor than scientific. And beauty lies in the eye of the beholder...