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.How to keep weed fresh Copy article link to clipboard. Link copied to clipboard. Contents Moisture and mold in marijuana The best temperature to store your cannabis Light
How To Store Weed & Keep it Fresh (Without Smell)
Cannabis goes through a very long and complex process before ending up as the dry herb we all buy; however, storage needs to be handled a specific way as well. Cannabis – like any other plant matter – can go bad. If not properly stored, it could accelerate potential damage (or at the very least, quickly lose its potency).
Properly storing marijuana ensures increased longevity and maintains quality. That being said, let’s take a look at how to properly store your weed.
At a Glance
- Airtight glass jars are the best storage method, avoid any long term use of plastic or tin.
- Container sizes should be just big enough to hold your stash. Keep strains in seperate jars.
- Keep containers in a cool, dry place. Away from any heat, light, or humidity.
- For long term storage consider using a humidity pack (like Boveda).
- Cannabis can spoil, expire, or go bad if not stored properly.
Best Container Practices
Glass Vs. Plastic
Plastic Tupperware containers and bags are a dime a dozen these days. Chances are everyone has them at home, since they’re cheap and can be bought in bulk. Unfortunately, these aren’t what you want to use when storing cannabis.
It’s critical that marijuana be kept away from plastic at all costs, as storing it in this material could reduce its potency. Static electricity in the plastic attracts plant matter called trichomes, which are hair-like extensions or growths on the skin of some vegetation. In cannabis, these tiny appendages produce the cannabinoids and terpenes responsible for its effects. By ripping them away, plastic dramatically reduces your herb’s strength.
Glass containers, on the other hand, don’t generate this kind of static, so the trichomes are safe. Specifically, mason jars are the best option, due to their glass lids and rubber seals. Alternately, most head shops sell their own line of jars specifically designed for cannabis storage.
Container Size Matters
Keeping marijuana away from plastic is a good first step, but there’s still more to consider when storing it. Specifically, the size of the container needs to be appropriate.
Another major objective is to keep as much air out as possible. Since we can’t use an airtight plastic bag, the most effective way to reduce air volume is to fit as much as possible in each container. Marijuana can vary in humidity and volume, so it may be necessary to eyeball it at times, but there is a general guideline.
Ideal Jar Sizes for Stash
- 2oz jar – 3.5g (eighth)
- 4oz jar – 7g (quarter)
- 8oz jar – 0.5oz (half ounce)
- 16oz jar – 1oz (full ounce)
Keep Your Strains Separate
Another mistake is mixing all your strains into the same container. While this isn’t necessarily catastrophic, it could alter the flavor (if that’s an important variable) but also make organization more difficult with multiple strains.
There are some best practices when it comes to cannabis storage locations. The main objective to protect your weed from humidity, drying out, or losing its trichomes.
Where To Store
Cannabis is best stored in a cool, dry place with no light exposure (or at least in a dark jar that can keep light away if need be). In this case, the best choice is a a glass jar – placed in a closet, drawer, cabinet or cupboard. All of these are usually closed, remaining dark and dry.
Where NOT To Store
Near Heat Sources
Your storage efforts could be useless if the location of the closet, drawer or other dark space could be affected by something external. For instance, never place the cannabis in a cabinet near a heat source, such as above the stove or a radiator. Doing so will dry out the herb. Darkness is also important because light (especially sun light) will damage the trichomes.
Fridge or Freezer
Some people like to wrap their marijuana in aluminum foil and leave it in the freezer to preserve freshness. Unfortunately, cannabis isn’t a bag of fresh strawberries. A freezer’s temperature doesn’t remain constant. Instead, it fluctuates with the motor kicking in once the area reaches a set maximum temperature. Consequently, this opens up the possibility of bacterial growth, resulting in spoilage.
Another problem with freezers is that, once again, they affect the marijuana’s trichomes. In this case, these extensions solidify like icicles, easily breaking away from the plant matter and reducing its potency.
Humidors or Cigar Boxes
There’s also a reason why cannabis needs to be stored in a dry place. Humidity tends to be a breeding ground for some very nasty things. Too much moisture is an open invitation for the plant matter to attract mold and bacteria, resulting in decay.
In some cases, people have humidors for storing cigars and other tobacco products. It’s essential to understand that cannabis and tobacco are two very different plants. Conditions that favor the former aren’t necessarily going work for the latter. The temperature and humidity in these devices isn’t appropriate for storing dry herb.
Battling Humidity and Dryness
We’ve already established that moisture is marijuana’s enemy. But the same can be said for dryness. For instance, leaving herb exposed in an arid area will cause the plant matter to dry out. Unfortunately, it’s hard to control these factors with pinpoint accuracy, as the cannabis has to settle for the best environment available; however, there are steps you can take to actively adjust humidity.
If you’re storing your weed short term (a few weeks), then don’t sweat it. Keep your stash in an air tight mason jar and you’ll be all set.
Best Method of Controlling Humidity
If you live in a humid or dry climate it can be a lot of work maintaining the quality of your weed. Controlling your house humidity with appliances is one solution. But if you really want to take control then humidity packs are a life saver.
Boveda packs are now available, which automatically adjust and balance humidity in any surrounding material. These are small packages that contain a water-salt solution, allowing them to regulate humidity. Using a process called “reverse osmosis,” the devices contain a membrane which (thanks to reverse osmosis) allows only water vapor to be exchanged back and forth between the pack and its environment.
The relative humidity (RH) levels are pre-set, so it’s important to read the percentage on the package before purchasing. Cannabis is in good shape as long as the RH is 55–62%.
The Orange Peel Tactic: Does It Work?
Home remedies always generate a buzz, which is why the “orange peel tactic” for controlling humidity really took off. The theory behind it is that dropping a few orange peels into a container of weed will re-humidify it. This actually does work, but it’s a double-edged sword.
The premise is pretty straightforward. Place the buds in an airtight container (preferably glass, of course), add some orange peels and seal them in. The dry cannabis regains a great deal of moisture within three to four hours.
Sadly, there’s a downside. While orange peels do help reinvigorate dry weed, they can also carry mold. We already know that mold provides its own set of problems. People intending to use this method should keep an eye on their marijuana and watch for signs of decay or infection, among other things. Moldy cannabis has the potential to be quite dangerous.
The Dangers of Mold
Speaking of mold, let’s see exactly why this is something nobody wants to see on their marijuana.
Mold thrives in moist environments, so any locked-in moisture provides the perfect spot for mold to flourish. In short: if you suspect your stash has grown mold, throw it out. Don’t risk it. Smoking moldy weed can be very, very bad news.
But there’s something much more sinister out there as well. Some sketchy dispensaries actually add moisture to their herb in hopes of increasing its weight. Water is quite heavy, so this can really make a difference. If someone purchases cannabis from a place like this, not only could their investment be ruined by mold, but they were essentially scammed in the process.
Of course, people who don’t notice moldy cannabis have much bigger things to worry about, depending on the specific species.
Types of Mold
Aspergillus makes its home in virtually any moist environment. Odds are, people have come across this one at some point or another. It’s known to cause things like lung disease, food spoilage and even smelly shoes.
Also known as “bud rot,” Botrytis is often found in grapes, but also damaging to cannabis. In fact, it can even kill an entire plant.
Penicillium is an interesting type of mold. As the name suggests, it’s used in the creation of the revolutionary antibiotic, penicillin. Certain versions are also used to make cheese; however, there are other sub-categories that do the complete opposite. Some Penicillium strains are highly destructive, not only to cannabis, but humans and animals as well.
What Should I Do With Moldy Weed?
Mold spores can effectively survive the extreme heat of being smoked, and can lead to some serious illness. If you live in a legal area, and purchased from a dispensary or licensed provider you must report it immediately so that no one else gets sick. It’s no different from buying contaminated food from the grocery store, obviously you’ll want a reimbursement but it helps keep their facilities under health check, and warns other potential consumers.
Does Marijuana Expire?
Mold is one thing, but what about long term storage. will your stash eventually just go bad?
All organic matter eventually expires or goes bad to some degree, and cannabis is no exception. The exact amount of time it takes varies depending on a lot of things. Commercially produced derivatives (oils, shatters, etc.) will be good for one or two years. Cannabis buds usually begin to degrade within a few months.
Longevity is also dependent on the strain itself and, of course, how it’s stored.
The interesting thing about marijuana spoilage is that it can either become drier or moister as it ages. Again, this is entirely dependent on the storage method and surrounding environment.
Dry marijuana isn’t a huge concern. While the potency will be reduced and smoking will be much harsher, there’s no risk to personal safety or health.
Moist cannabis, on the other hand, could pose a risk. Once more, this brings us back to the issue of mold and its ill effects. If the old dry herb seems to have gained moisture, it’s imperative to check for signs of mold. Moldy cannabis should never be smoked.
Signs of Spoilage
Change in smell is a classic sign that the weed has gone bad. There will be a less potent odor, while the aroma itself will seem strange. It’s difficult to describe in text, so this is a matter of judgment. If the herb smelled a certain way when it was fresh and now smells different after some time, then it’s likely that the cannabis is spoiled.
Change in texture is another classic sign. Fresh buds are slightly damp and spongy – almost bouncy – to the touch. An easy way to check for spoilage is to handle the herb and see if it crumbles. If it does, then the weed is past its prime.
Color changes aren’t just a sign of spoilage, they also indicate danger. Color changes indicate that mold could be present on the leaves. Look very closely, as mold can sometimes look like trichomes. Moldy cannabis could also darken in color or show discoloration (white or black) in specific spots.
Cannabis Storage Without Smell
Discretion is something a lot of marijuana users – medical or recreational – often value. There’s still a great deal of stigma attached to cannabis, while some medical recipients don’t want to advertise this confidential information to people who enter their home. This is perfectly fair and understandable. Fortunately, odor can be controlled.
Airtight mason jars are a good start, but they’re not foolproof; you may still find a bit of scent escaping. These jars will naturally breathe, this isn’t necessarily a bad thing, but it might be if you’re trying to mask the smell.
If you need to mask the smell in a hurry – here’s a few quick temporary solutions:
- Place your buds in a mason jar, and duct tape the outside of the jar.
- Empty prescription bottles – keep in mind plastic is not a good long term storage option for cannabis buds. Then place the bottles in a zip-sealed plastic bag.
- Vacuum sealed containers work, but are also usually plastic.
Longer term smell proof solutions:
- Check out some “skunk proof” bags from StashLogix or from your local headshop.
- Use multiple layers of storage – keep your airtight mason jars in a tightly closed drawer or cabinet.
- Use charcoal smell absorbent packs and keep them in the drawer.