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how long will weed stay fresh

How to keep weed fresh

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Contents

  1. Moisture and mold in marijuana
  2. The best temperature to store your cannabis
  3. Light and oxygen change cannabis composition
  4. Extending the shelf life of weed
  5. 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

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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

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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

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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 long is my weed good for? Leafly’s guide to storing cannabis

At some point in our cannabis consumption, we’ve all asked ourselves, “How long is my weed good for?” Maybe you’ve found a few nugs tucked in your winter jacket from last year’s ski trip, or when harvesting a medical crop you may need a way to safely store the excess buds until you’re ready to consume the fruits of your labor.

Like a fine wine cellar or whiskey barrel, properly dried and cured cannabis is best when kept in a cool, dark place. While there is no steadfast expiration date for cannabis, if you store it well it should last about six months to one year before losing considerable potency and flavor.

However, before you spark up that old weed, there are a few key elements to consider when storing cannabis for any extended period.

Explore marijuana storage options

What’s the best way to store weed?

Ideal temperatures for storing cannabis

Mildew and other molds on cannabis and other organic matter thrive in temperatures between 77° and 86° F, so basic precautions of keeping your cannabis in a cool, dark place will go a long way. Excessive heat can dry out the cannabinoids and terpenes that have taken months to develop. When these essential oils get too dry along with plant material, it can result in a hot, harsh smoke.

Lower temperatures also slow the process of decarboxylation of cannabinoids, the process in which THCA converts into the intoxicating cannabinoid THC. THC eventually degrades into CBN, a cannabinoid with different effects and properties. Additionally, warm air holds more moisture than cold air, which brings us to the next consideration.

Humidity factors for cannabis storage

Humidity control is paramount to keeping mildew and other mold contaminants away from your cannabis. Keeping your cannabis stored in a controlled environment with the proper relative humidity (RH) ranges can be a bit of a balancing act, but the general consensus is to keep cannabis between 59% and 63% RH when stored to maintain and enhance color, consistency, aroma, and flavor.

Keeping your RH below 65% reduces the chances for mold to occur. However, if your RH drops too low, you risk your trichomes becoming brittle and drying out the essential oils.

Light settings for storing cannabis

Harmful UV rays break down many organic and synthetic materials. Similar to the way your grass turns brown at the end of a long sunny summer, or how a car’s paint begins to fade when it is not garaged, UV rays will degrade your cannabis over time.

A study conducted at the University of London in the 1970s concluded that light was the single biggest factor in the degradation of cannabinoids. The same study concluded that cannabinoids maintain stability for up to two years when stored under the proper conditions, though it can remain effective and safe to consume for much longer as the essential oils slowly break down over time. Storing your cannabis out of direct light will also help you control the temperature.

Air control for cannabis storage

Double-check jar tightness to ensure every terpene is conserved. (Leafly)

While cannabis needs oxygen during growing and curing, storing your cannabis in a container such as a Mason jar with just the right amount of air is crucial to keeping it fresh and true to its original form. Having too little air can greatly affect the relative humidity, especially if the buds are not completely dried before storage.

Too much air, on the other hand, will speed up the degradation process as the cannabinoids and other organic matter are exposed to oxygen. There are a variety of hand and electric vacuum pump attachments available for canning jars that will help you minimize oxygen exposure.

How to store your weed

Do – store out of direct sunlight in a cool, dry place

Do – store in containers with a neutral charge, like glass Mason jars

Do – use hygrometers or products like Boveda to monitor and control RH levels

Do – vacuum seal jars and containers to minimize oxygen exposure

Do – separate your strains to maintain their individual flavor profiles. Label them with a date using a Sharpie. It sucks when you mix up strains.

Do – look for the many exciting new ways to store your cannabis. The cannabis industry is growing every day, with new products and companies like Cannador and The Bureau designing solutions for all of your cannabis storage needs.

Do — not stress about storing weed. The best way to get the most out of your herb is to smoke it in a timely fashion!

How not to store your weed

Don’t – store in the refrigerator. The fluctuations in humidity and temperature can actually increase your chance of mold and mildew. If you do refrigerate, vacuum-seal completely. Cold buds will scavenge water from the air, ruining the flavor. Allow container enough time to return to room temperature before re-opening.

Don’t – store in the freezer. Freezing temperatures cause the fragile trichomes to become brittle and break off like little icicles when handled. If you do freeze, vacuum-seal completely and keep frozen. Since a frozen bud scavenges water from the air, ruining the flavor, allow frozen container and buds enough time to return to room temperature before re-opening.

Don’t – store in cheap plastic bags or containers. Plastic often has a static charge that can attract precious trichomes. If you must use a plastic bag, only use it for short-term storage of small quantities of cannabis. Or use a higher-quality bag like a Smelly Proof bag.

Don’t – store above or around electronics or appliances that give off heat. Heat rises—instead, store your cannabis in a low cupboard, shelf, or in the basement of your house, much like a wine cellar.

Don’t – use a tobacco humidor. Most use cedar wood, which has oils that transfer and can influence the flavors of your cannabis. They also tend to employ sponges that use propylene glycol to regulate humidity and can oversaturate your cannabis.

Don’t – store grinders, pipes, or other paraphernalia with your cannabis. The ash and resin from burnt cannabis tends to linger and will stink up any storage container. Also, it is simply good etiquette to keep your supplies separate and clean.

Other factors for storing your marijuana

Products infused with cannabis, such as edibles and other perishable creations, will have different storage guidelines. Use by expiration date. Keep locked in a container to avoid accidental cannabinoid exposures. Refrigerate as directed.

Alcohol tinctures and other cannabis concentrates also degrade based on heat, light, humidity, and time. Keep extracts sealed tight in their containers in a cold, dark, dry place. While flower shelf-life is usually measured in a year or less—extracts and tinctures can be fridge-stable for years.

Find out about storage options to keep your marijuana fresh for longer. Learn more about the best ways to store weed at Leafly.com.