Does Weed Go Bad & How Long Does it Last?
It’s a classic scenario: you’re out of bud and in your frantic search for more you discover a long-forgotten baggie of flower somewhere in the back of your closet. You’re excited about your find. But wait: how long does weed last? How long is weed good for? Can you still smoke that old, dried out marijuana? How long does weed stay good, and what happens if you smoke weed that isn’t fresh? This guide has all the information you need.
How Long Does Weed Stay Good: The Basics
Let’s get to the heart of the matter. How long is weed good for? Under ideal storage conditions, cannabis can actually stay relatively fresh for a surprisingly long time.
If it’s been properly harvested, dried, cured, and then stored, you can expect your weed to stay fresh for anywhere from six months to a year.
If you’ve done an exceptionally good job of storing your bud, and you’re a little bit lucky, you may be able to stretch that timeline even further. Possibly to the point of approaching two years.
But for most weed smokers, conditions are less than ideal. In the absence of humidity controlled storage containers, and assuming that your weed will encounter some degree of light and the temperature might be less than perfect, don’t expect to get a full year out of your weed.
So how long does weed last? In general, try to consume all your weed within six months of purchasing it. But, of course, if you’ve invested in high-quality storage equipment, then you can push it out to the year mark.
How Long Is Weed Good For: The Scientific Answer
Now that you have a general idea for how long does weed last, let’s get into the more scientific answer. First, it’s important to understand what actually happens to marijuana as it ages.
Essentially, all the chemicals that make marijuana special break down. Over time, many of the cannabinoids and terpenes found in cannabis slowly break down and lose potency.
As the terpenes break down, your bud loses flavor and scent. As a result, old bud is relatively tasteless and lacks that distinctive, sharp odor that fresh weed is supposed to have. Sometimes, old weed will end up tasting harsh and nasty. Either way, when the terpenes have broken down, your weed won’t taste or smell the way it’s supposed to.
Similarly, and probably more importantly, cannabinoids also break down over time. Old, worn out bud won’t be as potent because a lot of the THC will have broken down and dissipated.
And here’s where we can get very precise with figuring out how long is weed good for. Fortunately, the United Nations Office on Drugs and Crime has looked into things for us.
Their researchers found that, on average, cannabis plant matter loses THC potency at this rate:
- After one year, weed loses roughly 16% of its THC.
- Two years in storage results in a loss of 26% of its THC.
- Weed loses 34% of its THC after three years.
- After four years in storage, weed loses 41% of its THC.
How Long Does Weed Last: Is Your Weed Bad?
Let’s return to that old bag of weed you found at the back of your closet. How do you know if it’s bad? Basically, you’re looking for a few things:
- Is it moldy? If your weed was too moist or humid, it may develop mold. Do not smoke moldy weed!
- Is it dried out? If your bud has crumbled into dust, it’s obviously too old.
- Does it smell fresh? Old marijuana lacks the crisp scent of fresh weed.
- Does it break apart? If it’s spongy and doesn’t make any sounds when you pull apart a nug, it might be damp and moldy. If it instantly breaks down into dry dust, it’s too old.
How Long Does Weed Stay Good For?
If you determine that your weed has gone bad, it’s not the end of the world. Technically speaking, you can still smoke it. It just won’t taste very good. And since most of the cannabinoids have probably already broken down you probably won’t get very high.
But smoking old weed won’t kill you or make you sick. The only exception is moldy marijuana. If your flowers have encountered too much moisture they might get moldy.
If you see discolored spots, white fuzzy mold, or if it smells like anything other than cannabis, don’t mess with it. Smoking or otherwise ingesting mold can definitely make you sick or worse, so steer clear.
Now that you know the answer to the question, how long does weed stay good, what should you do to keep it fresh? To preserve your bud for as long as possible, practice proper storage techniques.
Try your best to control temperature and humidity. Keep it away from direct sunlight, and store it in a cool, dry, dark location. With a little bit of care and some basic equipment, you can get the most of your bud.
So, Does Weed Go Bad?
Yes, weed goes bad. In fact, there are a couple different ways it can go bad. On one hand, if your weed sits unused for too long, or you leave it exposed to too much light or open air, it will simply dry out and turn into dusty, crumbly, ineffective flower. On the other hand, if your weed is exposed to too much humidity or other contaminants it could go moldy. And you do not want to inhale mold smoke. Doing so can make you sick.
Beyond the possibility of getting sick from bad weed, keeping your weed fresh will give you a better product and a better cannabis experience. The longer cannabis is exposed to environmental factors such as light and air, the more the cannabinoids and terpenes deteriorate. So if you want weed that will taste and smell great, while getting you super high, take care of your bud the right way.
How to Keep Weed Fresh for Longer
Different cannabis products have slightly different needs if you want to keep them fresh and potent. Here’s a quick breakdown of how to keep different cannabis products fresher for longer:
To keep flower fresh, you need to store it properly. This includes limiting exposure to light and open air, and maintaining a proper humidity level, typically somewhere in the range of 54 percent to 63 percent.
To accomplish all this, store your bud in either a small glass Mason jar or a container designed specifically for marijuana. Keep the lid on tight, don’t open it very often, and keep it in a cool dark place.
And for humidity control, you can either toss in a humidity control pack—check out Boveda, Integra BOOST, or a similar product—or if you want to step up your game to pro level, you can store your weed in a dedicated cannabis humidor such as the Apothecarry, Cannador, or another similar product.
To keep edibles fresh, leave them in their original package and store them in a place that’s away from open air and direct light. Be sure they’re in a cool location, as many types of edibles—especially things like hard candies and gummies—can easily melt.
The best way to keep your concentrates fresh and potent is to store them in small containers designed specifically for dabs. These are typically made out of glass, silicone, or a similar material. Keep the lids on tight and store the containers in a cool, dark place.
As with any other cannabis product, it’s best to keep your vape pens away from direct light. Because the cannabis oil is already inside an airtight cartridge you don’t really need to worry about humidity or exposure to air. As a final tip, store your vape pen standing upright, as this will keep all the oil at the bottom of the cartridge, ready for immediate use.
At some point, most weed smokers find themselves asking, how long does weed last?
How to keep weed fresh
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- Moisture and mold in marijuana
- The best temperature to store your cannabis
- Light and oxygen change cannabis composition
- Extending the shelf life of weed
- Frequently asked questions
Over the years, cannabis packaging in legal or medical marijuana regions has become more sophisticated, with features designed to maintain freshness. The packaging on your marijuana products might have a harvest date on them, but flower doesn’t come with an expiration date. So even with producers improving their packaging, you might find yourself wondering: how long does weed stay fresh?
About the two worst ways you can store your bud are on a tray, exposed to oxygen and light, and in a plastic sandwich bag, just like a dealer’s bags that are common on the illicit market. A number of environmental factors affect how well the plant grows, but cannabis storage is also a key component of quality and freshness. Cannabis needs the right balance of conditions to remain fresh.
Cultivators go to great lengths to ensure your flower is packaged with optimal moisture content, usually in opaque packaging to keep light out. You’re probably wondering why you still see transparent and clear containers lining your dispensary’s shelves.
Well, old habits die hard and the practice of seeing and smelling the product on the shelf is still a key component for many people when it comes to deciding what to purchase. Some companies have even started replacing the oxygen in their packaged flowers with nitrogen to help maintain freshness.
For the best possible marijuana experience, you need to know how to keep weed fresh and how to store weed properly. This guide will give you everything you need to know.
Moisture and mold in marijuana
Moisture and water make a big difference when it comes to degrading the shelf life of cannabis.
While no two cultivators dry their flowers in the same way, all cultivators dry their flowers and then put them through a process called curing.
When cannabis is properly cured, it allows the moisture that is trapped inside the bud to slowly dissipate from the flower without changing any of the cannabinoids or losing terpenes. Once the flower has the perfect moisture content, usually between 6% and 9%, it is placed into packaging from which excess oxygen has been removed. When you take it home, it’s important to try to maintain that balance.
Once the flower has the perfect moisture content, it is placed into packaging from which excess oxygen has been removed. When you take it home, it’s important to try to maintain that balance. Photo by: Gina Coleman/Weedmaps
If you lose too much moisture, it can change the integrity of your flower. Your flower will become brittle and lose essential terpenes that affect potency and taste. On the other hand, with too much moisture or water, the consequences are more serious. So serious, in fact, that the American Society for Testing and Materials (ASTM), which develops technical standards across many industries, published the “Standard Specification for Maintaining Acceptable Water Activity (aw) Range (0.55 to 0.65) for Dry Cannabis Flower” in May 2018.
The ATSM defines water activity as “the (quantitative) capability of the cannabis flower in a sealed container to affect the humidity of the container’s headspace air.” Headspace is the air that surrounds the flower. Water activity measures vapor pressure against pure water. If water activity is 0.55, it is 55 percent of water.
During storage, water activity cannabis should remain within a range of a minimum of 0.55 and a maximum of 0.65. Water activity increases with temperature, which is why light and temperature control go hand-in-hand as best practices for how to keep weed fresh.
The relationship between moisture content and water activity is complicated, and the cannabis industry is still striving to determine the optimal moisture content for packaged flower.
What we know now is that a relative humidity level anywhere above 65% can significantly increase the likelihood that your weed will end up growing mold. According to the American Herbal Products Association, the drying process will dehydrate cannabis until it has a moisture content of less than 15%, and the curing process is where the remaining moisture is slowly removed to retain the volatile oils.
The best temperature to store your cannabis
To extend the shelf life of marijuana, it should be kept in a cool, dark place at or slightly below room temperature. The ideal temperature to store your weed is below 70 degrees Fahrenheit, or 21 degrees Celsius.
High temperatures combined with high moisture activity and relative humidity can lead to mold and mildew. Mold thrives between 32 and 120 degrees Fahrenheit, or 0 to 49 degrees Celsius, and growth is most active between 70 and 90 degrees Fahrenheit, or 21 to 32 degrees Celsius.
High temperatures and arid environments dry out your flower and evaporate sensitive terpenes, which ultimately change the effects and taste of the flower. This is why some cultivators skip drying and make live resin extracts to preserve all the monoterpenes that are lost during the drying process.
Lower temperatures are not as problematic, but they can make it harder for tetrahydrocannabinolic acid (THCA) to decarboxylate into tetrahydrocannabinol (THC). Lower temperatures will reduce the potency of the flowers when they are smoked or could make the trichomes brittle on the plant, causing them to break off when they are removed from the cold environment.
Light and oxygen change cannabis composition
Exposure to light is the biggest culprit when it comes to aging weed. This has been known since at least 1976, when a study published in the journal Pharmacy and Pharmacology explored what happens to the stability of cannabis under various conditions. It concluded that light is the single largest contributor to loss and deterioration of cannabinoids and suggested that “carefully prepared herbal or resin cannabis or extracts are reasonably stable for 1 to 2 years if stored in the dark at room temperature.”
Ultraviolet (UV) light will always degrade your weed, even if you store it safely in glass jars. So, while the clear glass Mason jars you see in the marketplace look nice, they won’t protect your purchase the way an opaque container will. If you really like to look at your marijuana, a brown container will filter out visible ultraviolet light — that’s why brewers use them to bottle beer. Meanwhile, green containers will block out roughly 30 percent of UV rays.
As time goes by, prolonged exposure to light and air will gradually convert THCA into THC. At the same time this is occurring, existing THC is being converted into cannabinol (CBN), a cannabinoid that does not create the intoxicating properties that THC delivers.
Ultraviolet (UV) light will always degrade your weed, even if you store it safely in glass jars. Photo by: Gina Coleman/Weedmaps
And it’s not just THC that’s affected. Cannabidiolic acid (CBDA) can transform into cannabidiol (CBD) with enough exposure, and THCV will degrade into CBV. During this time, your weed could potentially become less potent.
In addition to playing a role in the conversion of cannabinoids, oxygen can also oxidize essential terpenes and change the overall aroma of the flower into a grassy, haylike smell.
To reduce exposure to oxygen, make sure there aren’t many air pockets in your container. You should always store your weed in an airtight container. Don’t use very large containers to store small quantities of weed, as this leaves too much air inside the container with your herb.
Of course, it is inevitable that some amount of oxygen will get into your sealed package once it is open, but you can limit the amount of time that the jar is opened and the number of times it is opened.
If you store your weed in sealed bags, remove as much air as possible before sealing. Vacuum-sealing weed can be a reliable, long-term storage solution for your stash. If you go this route, be sure you follow these tips to avoid inadvertently damaging your weed:
- Try to avoid vacuum sealing your marijuana in plastic that contains bisphenol A (BPA). This chemical is a key ingredient in many types of plastic, but it has proven to be harmful to humans. And unfortunately, if you store your weed in plastic containing BPA, some of those dangerous chemicals could leach into your marijuana.
- Handle your weed delicately. Plastic easily builds up static charges that can pull trichomes off your buds. Trichomes are the cannabinoid- and terpene-rich hairlike glands all over cannabis flowers, so you’ll want to avoid damaging them.
If you plan on storing your vacuum-sealed weed in the freezer, know that freezing will also make your trichomes vulnerable to damage, as they will become brittle.
Extending the shelf life of weed
Knowing how to store weed properly will help you get the most out of your cannabis experience. Ultimately, the key to extending marijuana shelf life is all about limiting exposure to the elements. When it’s time to open your container, pull out your flower and immediately close your package. Don’t let it sit open, and avoid windy or highly ventilated areas.
To maintain the right level of moisture, use a salt-based control sachet to maintain the ideal relative humidity. According to the ASTM standards (D8197-18), “a salt-based control sachet designed to maintain a relative humidity of 0.55 to 0.65 in a sealed container can be used to maintain optimum storage conditions.”
Additionally, you can store your marijuana in a cannabis humidor box, which has been designed to maintain the ideal humidity for marijuana. There are currently several models available on the market.
Whatever you do, be sure you don’t use a cigar humidor to store your weed. Cigar humidors are typically lined with cedar wood. The oils in the wood help enhance the taste of cigars, but those same oils tend to harm cannabis. Similarly, humidors for cigars often use sponges or propylene glycol to create humidity that are ideal for tobacco, but are much too high for cannabis.
In the past, to remedy dry weed, people would add an orange peel to their bags to keep the moisture content, but this greatly increases the likelihood that mold would be introduced. In addition, the water activity of orange peels is unknown and the aroma of the peel could alter the flavor and aroma of your weed.
Nowadays, you can use the same humidity control packs, such as Boveda packs, to reintroduce moisture if it is too dehydrated. This will not reintroduce terpenes that were lost, but it will ensure that you don’t have a harsh smoking experience.
To keep your weed in tip-top shape as long as possible, take careful steps to avoid exposure to light, moisture, oxygen, and extreme temperatures. Photo by: Gina Coleman/Weedmaps
Like almost everything else, weed doesn’t last forever. Over time, changes to the molecular structure occur with exposure to heat, light, and moisture.
When cannabinoids and terpenes experience very high or very low temperatures, dry up, are exposed to too much moisture, or are left in the presence of light, chemical changes that will degrade the potency of the flower and could alter the taste and mouthfeel may occur.
As terpenes are exposed to environmental changes, they can oxidize or evaporate, creating a change in aroma and effects. And even though all weed degrades over time, the process can be slowed down if you control the temperature, moisture, and the amount of oxygen your flower is exposed to. To keep your weed in tip-top shape as long as possible, keep an eye on the harvest date on the packaging and take careful steps to avoid exposure to light, moisture, oxygen, and extreme temperatures.
Frequently asked questions
What’s the best smell-proof container for weed?
The simplest way to keep your stash smell proof is to make sure it’s stored in a solid airtight container with a sealable top. Sealable glass jars, like a Mason jar, are typically sufficient for storing your stash and keeping in the smell. Some cannabis consumers also use large medicine bottles to keep their stash from stinking up their living space. Online retailers also offer a variety of odor-proof containers designed specifically for weed storage.
Is refrigerating or freezing weed bad?
Refrigerating or freezing weed is definitely preferable to storing it in an area that’s too hot or humid. And though some cannabis consumers report successful long term weed storage through freezing, it’s more than possible to lose freshness and potency to icy temperatures, as trichomes may become brittle and break off more easily. Storing your stash in an opaque, sealed container, in a relatively cool place with minimal sunlight is your best bet for long term storage with minimal degradation.
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