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                            THC-resin Extraction
          reprinted from "Marijuana Hydroponics:  High-Tech Water Culture"          
                 by Daniel Storm, published by And/Or Books,
                          (c) 1987
                          Ronin Publishing,
                          P.O. Box  1035,
                          Berkeley, CA 94701
                          ISBN: 0-914171-07-0         

           Typed/edited by
                  The Deviant of The Works BBS 617/861.8976        
   
               Email: deviant@works.uucp
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        Since so much time, labor, and cost has gone into the production of
each plant, growers do not overlook utilization of the "shake" or leaves. 
Extraction involves the process of removing the essential oil, THC resin, from
the leaves remaining on the plant and those removed during pruning. This is
accomplished through the use of a solvent in which the oil will dissolve, which
is later separated from the plant material by passing it through an appropriate
filter. 
        The best solvent found to date is choloroform.  It is non-flammable,
which makes it safer to handle than ethanol.  Further, it has a low boiling
point (61 C., 142 F.), and a residue after evaporation of .0005 percent. This
low residue percentage means that virtually no trace solvent remains to contam-
inate the oil and cause an aftertaste, which is usually a problem encountered
with ethanol unless time-consuming distillation processes are used.  Another
important concern is that chorophyll is relatively insoluble in choloroform,
eliminating the heavy "green" taste that always results from ethanol extrac-
tions. 

       To initiate the extraction process, the leaves must be 
dried thoroughly.  This can be done by placing them on fairly absorbent paper,
chas newsprint, in a good sunny spot near a window.  (Fresh newsprint paper
can be obtained in most art supply stores.  The lead content of ordinary
newspapers makes them unsuitable for this purpose.)  The leaves are then
turned over every few days to ensure complete drying.  When they are
sufficiently and completely dried, the leaves should be brittle and crumble
easily between the fingers.

They are then placed in a blender or food processor and ground to a fine pow-
der.  Studies have shown that to achieve 90 percent extraction of the oil,
the plant material must be powdered.  This is because nearly as much oil is
contained in non-glandular internal tissues as is produced by the glandular
tri-chomes. 

       Next, a filter (a coffee filter will do) is placed over a clean Pyrex
beaker or Corning Ware dish.  The plant material is piled about halfway to the
top of the filter, and the rest of the material (if any) is saved in an air-
tight container.  Pour approximately 200 ml of chloroform into the blender or
food processor and slosh it around the sides.  This rinses out any oil that may
have adhered to the container's walls.  Choloroform is poured from the blending
container over the plant material until it reaches the top of the filter(adding
more chloroform if needed).  When the chloroform has completely fil-
tered in to the beaker or dish, this process is repeated by adding chloroform
until it again reaches the top of the filter.  Two extractions of the same
plant material are usually sufficient to remove all of its THC oil.

        Now the plant material is discarded; the same procedure is repeated
until the beaker or dish becomes full of solvent.  Now the beaker or dish is
placed on an electric stove or hot plate and heated slowly to a very low boil.
When the choloroform is being evaporated, the area must be completely venti-
lated!  In the early days of medicine, chloroform was used as an anesthetic
until harmful side effects (such as liver damage!) were discovered, so it is
clear that extreme care must be used when evaporating this solvent.  After the
solvent has been evaporated, the same procedure is repeated until all of the
plant material has been treated.  The oil is collected and stored in a glass
pipette.  These can be obtained at a scientific supply and are inexpensive.
The oil is drawn into the tube (this may be easier if the oil is first heated
 abit), and the tube capped at both ends.  Resin is best stored inside airtight
containers and in an area of low light and humidity.

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