Before extracting, you must prepare your herbs and load the herb tube properly, to create the best possible circumstances for the extraction. Herb grain size, how densely the herbs are packed, and proper filter placement will influence the amount and quality of your yield.
The herbs must be divided into small parts, approx. 1-10 mm in size, so the solvent (IPA) can reach all of the plant material easily.
Avoid cutting the herbs with a sharp instrument like a blender – cutting the plant cells open will expose a lot of chlorophyll and plant wax, effectively lowering the purity of your final extract.
The best, but also the most time-consuming way is to simply crumble your herbs using your fingers.
Alternatively, use a blunt instrument like an electric hand mixer with dow hooks. Place your herbs in a container just wide enough for the dow hooks to fit in also, and blend away. Do not use a glass container, as you could risk breaking the glass.
When crumbling your herbs, remove stems and seeds in the process. You do not need to remove all, but neither stems nor seeds add anything useful to the extract, so the more you remove, the higher the yield and quality of your final extract.
This video shows some possible ways to prepare your herbs, and how to load the herb tube properly: