Most food products and many medicines come with a sell-by or use-by date. These labels let consumers know when a product is out of date and may no longer be safe to use.
Now that cannabis products are moving into the mainstream, many of these products are also required to include expiration dates on their packaging.
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But do cannabis products really have a shelf life? What can you do to make your cannabis products stay fresh and viable as long as possible?
The answer, as with many things marijuana related, is complicated. Cannabis comes in many different forms, such as:
These products are the result of various extraction and preparation processes. So, you may be thinking that cannabis flower would be the best way to consume marijuana without other ingredients that can make it go bad. But whether you’re consuming cannabis flower or an extract, improper storage methods can affect a product’s viability, too.
All of these factors can combine and interact to affect how long a product stays fresh and potent, and whether using it poses any health risks.
The sell-by and use-by dates on the labels of foods and medications give buyers a sense of how long a product is likely to stay fresh and deliver its promised content. But it’s not always clear what happens if someone uses a product after these dates.
All three of these things can happen with cannabis products as well.
Over time, terpenes and cannabinoids in various cannabis products can degrade. This can cause them to lose potency, so that they have a weaker effect—or no effect at all.
Depending on how they’re processed, cannabinoids can degrade into a different kind of cannabinoid with different effects than expected. Some ingredients in cannabis can become harmful due to chemical processes that happen over longer periods of time. External toxins like mold and mildew can also develop on cannabis that’s been stored improperly for a long time.
Light, heat and moisture can affect the shelf life of dried cannabis, causing it to degrade, lose potency, or develop harmful fungus and mold. But these problems are largely due to improper storage. Excess heat can dry out cannabis, causing terpenes and cannabinoids to degrade.
When the molecules in cannabis terpenes and cannabinoids degrade, the result can be a change in the effects of the product, or its potency. Tetrahydrocannabinol (THC), the ingredient in cannabis that can get you high, can degrade into another cannabinoid, called cannabinol (CBN) when exposed to UV rays and oxygen. CBN, which has a different molecular structure than that of THC, typically causes drowsiness rather than an intense high.
High humidity, especially when combined with poor storage practices, can cause mildew and mold to develop in cannabis flower. Inhaling mold spores can cause health problems ranging from mild allergic reactions to severe lung infections and chronic symptoms like shortness of breath and wheezing.
The shelf life of cannabis products depends partly on how they’re produced. Take extracts, for example. Cannabis extracts like wax and shatter, as well as those used in tinctures and infusions, are produced by extraction processes that aim to preserve as many terpenes and cannabinoids as possible. But depending on the extraction method, impurities like lipids, or fats, from the cannabis plant, and other substances can remain.
Solvent-free extraction processes leave behind more impurities than those that involve solvents. A secondary filtration process using solvents, called winterization, can eliminate more impurities. But this kind of heavy processing can cause valuable terpenes and cannabinoids to degrade more quickly.
Cannabis extracts that contain high levels of lipids, or fats, can become harmful if they linger past their expiration date. Over time, these fats can oxidize, so that if someone smokes or dabs the product at higher temperatures, they can release toxins. Pure or nearly pure extracts, such as those used in tinctures and emulsions, can lose potency quickly as terpenes degrade.
Combining cannabis with other kinds of ingredients can also affect its potency and viability. Cannabis extracts in products like creams, salves and ointments may last longer than cannabis extracts alone do, thanks to the stabilizing effects of ingredients like oils, fragrances and other medicinal substances. But oils, including cannabis oil, can also become rancid after long periods of time, especially if consumers don’t properly store them.
The same is true of edibles. Cannabis is just one ingredient in a product like gummies or brownies. The other ingredients in these products are no different from products that don’t contain cannabis. Like any other foodstuffs, they can degrade relatively quickly.
Edibles often have an expiration date that’s clearly stated on the product label. This date reflects the product’s shelf life based on its overall ingredient list.
Light, heat and moisture are the enemies of cannabis products of all kinds. It’s important to store products in cool (not cold), dark and dry places to keep them fresh for as long as possible.
Cannabis flower should be stored in airtight containers away from heat and light. Oils and concentrates, too, should be kept away from excess heat and light that can cause ingredients to degrade or oxidize.
For products that contain cannabis alongside many other ingredients, such as edibles or topical creams and ointments, follow standard storage instructions and any provided sell-by dates for the products you have.
Use logic and read labels when it comes to edibles. If you wouldn’t want to eat a dried out cannabis-free brownie lurking in the back of your cupboard, you wouldn’t want to eat one with cannabis in it either.
Stored properly, many cannabis products can remain fresh, safe and potent for months, or even a year:
The expected shelf life of cannabis products depends on a multitude of factors. But careful storage and attention to a product’s own labeling can help you get the most out of your favorite cannabis products.
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