The oxygen in the air, static electricity, vapor migration, light, humidity and temperature all play a part in determining how long cured cannabis will maintain its integrity and quality.
While growing and curing, cannabis needs air. When we say it needs air, we mean it needs oxygen. But after properly curing cannabis, there is no need for oxygen. In fact over time, oxygen will break down the buds, dry them out and deteriorate them. Air is the biggest single problem for long term storage of cannabis. When cannabis is stored for any length of time it must be stored so that oxygen cannot get to it.
Although a bolt of lightning is a vivid demonstration of static electricity, we tend to think of static electricity coming from rubbing things. Some plastics bags used for food storage will generate static electricity when rubbed up against many materials. If static electricity is produced near cannabis it will attract the trichomes. That is why it is usually recommended that cannabis not be stored in plastic bags, since any static electricity will make the cannabis less potent.
A disadvantage of storing cannabis in a typical plastic bag is vapor migration. The term “migration” refers to the diffusion of substances from a zone of higher concentration, such as the inside of a plastic bag, to one of a lower concentration, such as the air outside of the plastic bag. This migration is indicative of the stored cannabis losing its scents and flavors into the air.
It is always said not to store cannabis in light. What is really meant is not to expose the cannabis to ultraviolet light (UV). In the case of cannabis ultraviolet light has the effect of slowly vaporizing the THC and CBD from the cannabis and ultimately adversely affecting its potency.
An often-cited study published by the University of London found light to be “the greatest single factor in loss of cannabinoids.” A study at the Boston University School of Medicine showed that cannabis stored over a one-year period had a 36 percent decrease in THC when stored in the light compared to a 13 percent decreased when stored in a dark environment.
When cannabis is stored the relative humidity must be closely monitored. Too much moisture in the air will make cannabis susceptible to mildew and mold. Too little moisture will result in the trichomes becoming brittle and the essential oils drying out, which will degrade the cannabinoids and terpenes even if the air temperature is optimal. Research suggests that a relative humidity level between 59 percent and 63 percent is ideal to keep cannabis fresh in terms of potency, aroma, flavor, texture and color.
Monitoring the humidity level of cannabis while it is stored in an air tight container is not always easy. However, failure to monitor the humidity level in the container and adjust it to the proper levels will result in the cannabis drying out over time.
Storing cannabis at too high of a temperature can ruin the cannabis. Mold and mildew thrive on cannabis in warm temperatures between 77° and 86° F. Furthermore, excessive heat can dry out the cannabinoids and terpenes. When these essential oils get too dry the quality of the cannabis deteriorates.
When cannabis stored in a glass jar gets too hot it begins to sweat. This increases the relative humidity inside the jar, putting the buds at risk of molding.
When storing cannabis make sure that there is no oxygen present, that static electricity cannot be produced, that the potential for vapor migration is removed, that the cannabis is protected from ultraviolet light, that humidity is closely monitored and that the cannabis is stored in a cool environment.