Solventless extraction is making concentrate without chemical solvents. You work only with what is available mechanically and physically.
Three main routes:
- Rosin pressing — heat and pressure between heated plates. Resin runs out.
- Dry sift — dry sieving through screens of a defined mesh.
- Bubble hash — ice water and mesh bags that separate the trichomes from the rest.
The difference against the butane route is what is left in the product. With solventless there is nothing to purge, because nothing was added. You usually pay for that in lower yield and a higher price.
It does affect flavour — solventless tends to be softer and cleaner. It changes nothing about which banger and what temperature it wants.