Curing is a process employed to naturally enhance the bouquet, flavour,
and texture of marijuana. Curing does not lower potency when done
correctly, although poor curing methods often result in some less of
Curing is not an essential procedure, and many growers prefer the
"natural" flavour of uncured grass. Sweet sinsemilla buds usually are
Curing is most successful on plants
which have "ripened" and are beginning to lose chlorophyll. It is less
successful on growing tips and other vigorous parts which are immature.
These parts may only lose some chlorophyll.
Curing proceeds while the leaf is still alive, for until it dries, many
of the leaf's life processes continue. Since the leaf's ability to
produce sugars is thwarted, it breaks down stored starch to simple
sugars, which are used for food. This gives the grass a sweet or earthy
aroma and taste. At the same time, many of the complex proteins and
pigments, such as chlorophyll, are broken down in enzymatic processes.
This changes the colour of the leaf from green to various shades of
yellow, brown, tan, or red, depending primarily on the variety, but
also on growing environment and cure technique. The destruction of
chlorophyll eliminates the minty taste that is commonly associated with
There are several methods of curing, most of which were originally
designed to cure large quantities of tobacco. Some of them can be
modified by the home grower to use for small marijuana harvests as well
as large harvests. The methods used to cure marijuana are the air,
flue, sweat, sun, and water cures.
Air curing is a technique developed in the United States for curing
pipe and cigar tobacco. It was originally done in specially constructed
barns made with ventilator slats which could be sealed; a small shed or
metal building can easily be adapted for this use. However, this method
of curing works only when there is enough material to keep the air
saturated with moisture.
Wires are strung across the barn, and the marijuana plants or plant
parts are hung from them, using string, wire twists, or the crooks of
branches. The plants material should be closely spaced, but there
should be enough room between branches (a few inches) so that air
circulates freely. The building is kept unventilated until all the
material loses some chlorophyll (green colour). This loss occurs
rapidly during warm sunny weather because heat builds up, which hastens
the cure. In wet or overcast weather, the temperature in the chamber
will be cooler, and the process will proceed more slowly. If these
conditions last for more than a day or two, unwanted mould may grow on
the plants. The best way to prevent mould from forming is to raise the
temperature to 90F by using a heater.
After the leaves have lost their deep green and become pale, the
ventilator or windows are opened slightly, so that the temperature and
humidity are lowered and the curing process is slowed. The process then
continues until all traces of chlorophyll are eliminated. The entire
process may take six weeks. Then the ventilators are opened, and an
exhaust fan installed if necessary, to dry the material to the point
that it can be smoked but still is moist, that is, bends rather than
crumbles or powders when rubbed between thumb and forefinger.
Flue curing differs from air curing in that the process is speeded
up by using an external source of heat, and the air circulation is more
closely regulated. This method can be used with small quantities of
material in a small, airtight curing box constructed for the purpose.
Large quantities can be hung in a room or barn as described in Air
A simple way to control the temperature when curing or drying small
amounts of marijuana is to place the material to be cured in a
watertight box (or a bottle) with ventilation holes on the top. Place
the box in a water-filled container, such as a pot, fish-tank, or
bathtub. The curing box contains air and will float. The water
surrounding the box is maintained at the correct temperature by means
of a stove or hotplate, fish-tank or water-bed heater, or any
inexpensive immersible heater. Temperature of the water is monitored.
With the marijuana loosely packed, maintain water temperature at 90
degrees. After several days, the green tissue turns a pale yellow-green
or murky colour, indicating yellow or brown pigments. Then increase
temperature, to about 100 degrees, until all traces of green disappear.
Raise the temperature once again, this time to 115 degrees, until a
full, ripe colour develops. Also increase ventilation at this time, so
that the marijuana dries. Plants dried at high temperature tend to be
brittle; so lower the temperature before drying is completed. This last
phase of drying can be done at room temperature, out of the water bath.
The whole process takes a week or less.
Marijuana cured by this technique turns a deep brown colour.
Immature material may retain some chlorophyll and have a slight
greenish cast. Taste is rich yet mild.
Sweat curing is the technique most widely used in Colombia. Long
branches containing colas are layered in piles about 18 inches high and
a minimum of two feet square, more often about ten by fifteen feet.
Sweat curing actually incorporates the fermenting process. Within a few
hours the leaves begin to heat up from the microbial action in the same
way that a compost pile ferments. Then change in colour is very rapid;
watch the pile carefully, so that it does not overheat and rot the
colas. Each day unpack the piles, and remove the colas that have turned
colour. Within four or five days, all the colas will have turned
colour. They are then dried. One way to prevent rot while using this
method is to place cotton sheets, rags, or paper towels between each
double layer of colas. The towels absorb some of the moisture and slow
down the process.
Sweat curing can be modified for use with as little marijuana as
two large plants. Pack the marijuana tightly in a heavy paper sack (or
several layers of paper bags), and place it in the sun. The light is
converted to heat and helps support the sweat.
Another variation of the sweat process occurs when fresh undried
marijuana is bricked. The bricks are placed in piles, and they cure
while being transported.
A simple procedure for a slow sweat cure is to roll fresh marijuana
in plastic bags. Each week, open the bag for about an hour to evaporate
some water. In about six weeks, the ammonia smell will dissipate
somewhat, and the grass should be dried. This cure works well with
small quantities of mediocre grass, since it concentrates the material.
A quick way to cure small quantities of marijuana is to loosely
fill a plastic bag or glass jar, or place a layer between glass or
plastic sheets, and expose the material to the sun. Within a few hours
the sun begins to bleach it. Turn the marijuana every few hours, so
that all parts are exposed to the sun. An even cure is achieved in one
to two days. Some degradation of THC may occur using
Unlike other curing methods, the water cure is performed after the
marijuana is dried. Powder and small pieces are most often used, but
the cure also works with whole colas. The material is piled loosely in
a glass or ceramic pot which is filled with luke-warm water. (When hot
water is used, some of the THC is released in oils, which escape and
float to the top of the water.) Within a few hours many of the
non-psychoactive water-soluble substances dissolve. An occasional
gentle stirring speeds the process. The water is changed and the
process repeated. Then the grass is dried again for smoking.
THC is not water-soluble; so it remains on the plant when it is
soaked. By eliminating water-soluble substances (pigments, proteins,
sugars, and some resins), which may make up 25 percent of the plant
material by weight, this cure may increase the concentration of THC by
up to a third.
Marijuana cured by this method has a dark, almost black colour, and
looks twisted and curled, something like tea leaves. The water cure is
frequently used to cure dried fan leaves and poor-quality grass.