Marijuana trimmings, or bud trimmings, are left over after a grower harvests a crop and manicures the buds. This method also works for shake and other material that is not as dense as marijuana bud. For instructions on decarboxylating bud, see this.

When preparing marijuana to be eaten, made into a tincture, or some other method of ingestion other than smoking or vaporizing, it must first be decarboxylated. This is done so the active components of marijuana will be more easily absorbed by the human body.

Many people try to make some type of marijuana food or drink, only to have the resulting product provide very little psychoactive effect. The most common cause is not decarboxylating the marijuana enough, or in some cases not decarboxylating at all.

When a marijuana plant is harvested, most of the THC (tetrahydrocannabinol, the primary active cannabinoid in marijuana) is in its acidic form. This is called THCA, tetrahydrocannabinolic acid. THCA is not psychoactive to humans.

Curing and drying causes some of the THCA to convert into THC. Smoking or vaporizing also causes THCA to convert into THC. So when smoking or consuming it in a manner that heats the marijuana to a high temperature, some or most of THCA is converted to THC with no extra effort.

When eaten or drunk, an extra step called decarboxylation must be employed. This is accomplished by heating the marijuana under specific conditions prior to incorporating it into a recipe, or consuming it another manner.

Decarbing Trim

The first step is to decide how much mj trim to decarboxylate. If you are not sure, 14-28 grams is a reasonable amount for a first attempt.

After you decide how much trim to decarboxylate, the next step is to make sure it is dry so it doesn’t clump together.

If the trim clumps together there is a chance that it won’t decarboxylate evenly, so dry the trim before attempting to decarb it.

Bud trim is small leaves trimmed away from the bud, there should be no need to grind it. When marijuana bud is decarboxylated, it has to be ground into small pieces.

If there is any bud or dense material mixed in with the trim, grind it to a point where the particles are about the same size as marijuana when it is rolled into a joint, several times larger than grains of salt.

Place the dry marijuana trim in a pyrex dish or some other type of oven safe dish. Try to level the marijuana in the pyrex dish so it is roughly the same depth in all parts of the pyrex dish.

Making it relatively level and no more than about 1 to 1.5 inches/25 to 38 mm deep, is so the marijuana gets heated at the same rate.

If you were to dump the trim into a pile, or if it’s too deep, the material at the center will take longer to heat than the exterior, incomplete decarboxylation.

Wrap aluminum foil around the dish so it is well sealed. Some compounds in marijuana may vaporize when decarboxylating.

Keeping the marijuana as air tight as possible will allow any vapor to be absorbed by the marijuana instead of escaping into the air. Regular foil is ok if that is all you have available. Heavy duty foil is best and can be reused.

Set the oven to 240°F/116°C and wait until it reaches that temperature. If necessary, use an oven thermometer for accuracy. When it reaches 240°F/116°C, put in the pyrex dish containing the marijuana trim in the oven.

The length of time to keep the marijuana in the oven depends on how it will be consumed.

Step By Step

A) Decide how much marijuana trim to decarboxylate.
B) Place the trim in a pyrex dish.
C) Level the trim to roughly the same depth in dish.
D) Wrap aluminum foil around dish so it is well sealed.
E) Pre-Heat oven to 240°F/116°C.
F) When heated, put dish in oven.
G) Wait until decarboxylation time is finished.
H) Turn off oven heat.
I) Leave the door for the oven closed.
J) Wait until cool.
K) Remove from oven.

Notes

1 — The reason for keeping the temperature at or below 240°F/116°C is in order to minimize the chance of cannabinoids from being degraded by the heat. Once the temp goes over 250°F/121°C, there is a greater chance of heat having a negative effect.

2 — Dry bud trim can decarboxylate fairly quickly. If it gets too well done the first time you try, next time you work with trim that is dry, reduce the amount of time it gets heated. It should be medium to dark brown when finished, rather than black.

3 — Size of pyrex or oven safe dish: A larger dish will be able to hold more material. At the research center, where these tests were conducted, a set of three pyrex dishes are always at the ready in case of situations like this.

The smallest dish is 7 x 5 inches, it can hold up to about 28 grams of marijuana trim for decarbing.
The medium sized dish is 8 x 6 inches, it can hold up to about 42 grams of marijuana trim for decarbing.
The largest dish is 9 x 7 inches, it can hold up to about 56 grams of marijuana trim for decarbing.

With the set of three pyrex dishes, up to 4.5 ounces of marijuana trim can be decarboxylated at a time. The pyrex dishes are reserved for working only with marijuana, and marijuana extracts like hash oil.