Properly dried and cured cannabis flower buds burn evenly and have a smooth, rich taste. When smoked, the embers have an even glow and enter the body smoothly. When vaporized, there should be no apparent “green” taste.
If flower buds are dried too quickly, chlorophyll and other pigments, starch and nitrates or other fertilizer salts are trapped within plant tissue, making it burn unevenly and taste unpleasantly “green.” If buds are dried too slow, or not at all, they rot.
Gardeners can lose some or all of their crop to poor drying and curing cannabis techniques. Here’s how to do it right:
Drying converts 75% or more of a freshly harvested plant into water vapor and other gases and converts carbohydrates to simple sugars. Drying also converts chlorophyll and other pigments so that no “green” residuals remain.
You can harvest an entire plant, individual branches or strip flower buds from branches to dry. When stems are severed, the transport of fluids within the plant continues, but at a much slower rate. The natural plant processes slowly come to an end as the plant dries. The outer cells are the first to dry, but fluid still moves from internal cells to supply moisture to outer cells, which are dry. When the drying and curing processes occur properly, plants dry evenly throughout. Removing leaves and large stems upon harvest speeds drying; however, moisture content within the “dried” flower buds, leaves and stems can become uneven.
Drying time depends upon temperature, humidity and bud density. Ideal temperature is 60-70°F and the best humidity range for drying is 45-55%. Most flower buds will be dry enough in three to five days before passing to the curing process, but they may take longer. It can take up to two weeks before all chlorophyll — the stuff that gives the “green” taste — has dissipated from foliage. Big, fat, dense flower buds can take three to four days longer to dry than smaller buds. Gently squeeze buds after they have been drying for a few days to check for moisture content. Bend stems to see if they are dry. If the stem breaks rather than folds, it is ready to cure. The bud should be dry to the touch but not brittle. The bud should burn well enough to smoke when dry.
Even after plants, branches or buds have dried on screens or been suspended in a drying room for five to seven days and appear to be dry, they still contain moisture inside. This moisture affects taste, fragrance and cannabinoid content (potency). Curing will remove this excess moisture and all it contains.
Curing after drying helps remove any remaining chlorophyll, other pigments, latent fertilizer salts and so on that have accumulated in flower buds, leaves and stems. If dried too quickly, flower buds retain more chlorophyll and have a “green” taste, and when vaporized or smoked are harsh on the pallet and often burn too hot. For some, curing is not essential. In fact, some medical patients prefer the often minty flavor of uncured cannabis.
Curing also allows cannabis to fully dry so that mold does not grow when it is stored. Well-cured flower buds are soft and pliable but dry inside. Flower buds should feel like they are dry and only the dry pliable foliage is holding resin onto stems. Here’s how to cure bud:
Gently place “dry” flower buds in an airtight container. Clear and opaque turkey bags are popular. So are food-grade sealable plastic buckets. There are also bags that reflect heat and are airtight (when properly sealed) and infrared-proof, which protects them from heat.
Write the date on the containers and place in a cool, dry, dark place. Moisture inside buds will migrate from the center of the stem outward. Check the container after two to four hours to see if buds feel different. Gently squeeze a couple of buds to see if they feel moister now, but be careful, resin glands bruise easily.
Open the drying container two to three times a day for the first seven days to release moisture. Take a whiff the instant you open the container. The fragrance should be sweet and somewhat moist. Close the container quickly. If necessary, remove buds from jar for a short time to inspect for mold and disease.
After the first week, open containers once or twice a week for a quick whiff. Do not open too many times or the slow-curing process will stop. Some gardeners cure flower buds slowly for six months or longer. However, after two to three weeks they should be fully cured and remain fresh, firm and pliable. Flower buds can be sealed in containers and stored.
Light — especially ultraviolet (UV) rays from natural sunlight — heat and friction hasten biodegradation of resin glands and cannabinoids. Do not place dried cannabis in hot automobile glove compartments, and keep it away from heat vents and so forth. Friction and rough handling can bruise and rupture resin glands. Even with proper drying and curing, brutal handling of harvested cannabis will diminish cannabinoid content.
Originally published in the print edition of Cannabis Now.