Place 1/2 pound (about 230g) of marijuana (seeds and stems may be included) in a large double boiler or heat bath, cover with alcohol (about 1.9 l) and boil for 45 minutes. If available, pure grain ethyl alcohol may be used. Otherwise vodka may be used.
Because all the alcohol will be removed by evaporation before the tar is used, one may use isopropyl rubbing alcohol instead. Be sure not to use any denaturated alcohol as this will leave a horrid tasting residue.
Pay caution not to let the alcohol boil over. Remember that the boiling point is lower than that of water and that alcohol is combustible. The use of a gas burner is discouraged.
After the boiling strain the boiled materials and save the green solution. Add more alcohol to the mash while it is still damp and repeat the boiling (45 mins). Strain and combine the extraction with the first one.
Fill a cleaned double boiler half the way with the extractions. Heat without a lid in well ventilated conditions until the liquids have boiled down to half the original. Add more solvent to bring the liquids back to the halfway mark. After all the extractions are added this way continue boiling until the scent of alcohol is no longer detectable.
If 100% alcohol wasn't used there will be a considerable water content to be removed. To remove it place the extracts into a Pyrex baking dish and leave in the oven with the heat set to the lowest possible setting. After all the moisture is gone the tar can be scaped up while still warm and stored.
To remove any harsh tasting substances from cannabis tar boil in 5 volumes of water for 10 minutes, cool down to room temperature and refrigerate. Recover the tar and discard the water.
