✅ Updated 9/28/21

The cannabis plant requires months of growth and development to produce mature trichome heads worthy of extraction. The most successful growers take cues from the plants themselves, and wait until the resin glands reach the ripeness required to produce powerful medicine. And nature doesn’t hurry. 

Neither should solventless extractors. Once the cannabis flowers are harvested, they require time, and in some cases additional processing, to be ready for solventless extraction. How the cannabis is stored prior to processing can make or break the success of the extraction and determine the quality of the final product. 

Proper storage prepares cannabis material for extraction, whether the material is air dried and cured, or fresh frozen for hash production. With the right storing methods, extractors can also hold excess material for processing as it fits into the production schedule. But storage isn’t just about preparation, it’s about preservation. Proper storage maintains the best qualities of mature resin glands so that they can be efficiently extracted. Careless storage can ruin your chances of capturing the best that the plant has to offer. 

The type of extraction intended for the material is a primary consideration, which helps to inform moisture content requirements. Pressing unprocessed cannabis flowers for rosin requires moisture content in the 60-65% relative humidity range, while pressing bubble hash hinges less on concise moisture control (due to resin glands being hydrophobic, or repelling water). Storage methods contribute to the moisture content in a major way. 

If washing fresh frozen cannabis material for bubble hash is the objective, then correct freezing/storage methods are necessary to prepare the raw cannabis for production. 

The main questions to ask when determining storage methods are:

Regardless of the intended use for cannabis material, cold, dry, dark, and airtight are the general conditions to aim for when crafting a storage solution. 

Conservation is King

Storage prepares material for processing, for both fresh frozen and air cured cannabis. But another major function of proper storage is conservation of key components in cannabis, namely the terpenes and cannabinoids within the resin glands. These compounds deliver the therapeutic effect for the consumer, so their preservation and conservation is top priority. 

Terpenes are very volatile, which means they can easily evaporate, even at a slightly warm room temperature. By controlling temperature and airflow, we can minimize terpene loss. Similarly, cannabinoids are vulnerable to oxidation and degradation over time and with exposure to heat. Certain cannabinoids also transform from psychoactive to non-psychoactive forms, but proper storage can slow down this transformation.

Correct storage practices also prevent damage to the cannabis material which can occur in the form of mold and mildew growth, or speedy and excessive oxidation (a natural process that inevitably occurs over time).

What Are The Downsides of Improper Storage?

Improper storage practices can not only lessen the quality of the extract, but it can even completely ruin the material. For example, storing fresh buds immediately after harvest inside sealed glass jars will lead to mold growth, at which point the cannabis is unfit for use. Also, storage at high temperatures can speed up terpene loss and cannabinoid degradation. 

With excessive airflow, oxidation levels increase, which is a negative for the material as well. Airflow is important when dealing with fresh frozen material, because any oxygen that’s inside the storage containers inside the freezer will allow for freezer burn.

Cured Flower Storage

Air-cured cannabis flowers can be used for pressing flower rosin, or washed for bubble hash. For either extraction method, storing the flowers in sealed glass jars is best. After harvesting, the flowers are hung to dry for around ten days up to two weeks. Once the flowers have reached the point of dryness to where the stems snap or break cleanly instead of folding in half, they should be ready for jars. It’s best to keep a digital hygrometer inside the jars as well, to maintain a relative humidity of 60-65%. 

Once filled, the sealed glass jars should be kept in a cool, dry, dark place. If the flowers become too dry over time, there are ways to rehydrate the flowers as well. 

Vacuum sealing the bags is a good idea, just don't take all of the air out, to the point that the material gets shrunken down into a dense mass. This presses the delicate trichomes together with a lot of pressure, which can cause them to rupture. Leave just enough air in the bag to provide a cushion between bags when you stack them. This small amount of air left in the bags provides protection for the trichomes from getting damaged, which also reducing the oxygen in the bag. 

Oxygen around the material will cause freezer burn and oxidation. Check out our article about Fresh Frozen Cannabis to learn more about how to properly freeze cannabis.

If air cured flowers are being processed for bubble hash, they can be stored in sealed glass jars in the same way as the material for pressing flower rosin. 

Vacuum Sealing

Vacuum sealing is not only useful for fresh frozen material within the freezer, but it’s great for storage of cannabis flowers for either short or long-term. While it’s recommended to use plastic sleeves for the vacuum sealing process for fresh frozen (as they’re best coupled with the traditional vacuum sealing devices), there are also glass jar solutions that have vacuum sealing capacity. 

These units are self-contained and allow for air removal from the jar once the lid is sealed. These are excellent choices for storage of flowers, bubble hash, and dry sift to slow down the process of oxidation and cannabinoid degradation. Be sure the correct moisture content already exists within the material before sealing in the jars. 

Once the lid is sealed, use the integrated vacuum sealer on the lid to remove the air inside the vessel. This creates an excellent environment for the storage of any kind of cannabis material. Keep these jars in a cool, dark, and dry place for best results. Digital hygrometers are a good addition inside the jars as well, to keep an eye on moisture content over time. 

Induction Sealing

Heat induction sealers are created for the purpose of hermetic sealing, which is any type of sealing that makes a container airtight.  Heat induction sealers secure a foil laminate seal to the inside of a closure, creating an airtight environment for everything inside the container. This is the ideal environment for the long term storage of rosin, bubble hash, and even cannabis flowers. 

Induction sealing requires additional equipment you likely don't have at the house, but it's relatively straightforward and doesn't have to blow out your budget. Portable, handheld heat induction sealers are available on Amazon for under $200. 

To use the induction sealer, secure the laminate seal and the plastic lid onto the container holding your cannabis. Place the device over the lid, press the button, and an airtight environment inside the container is created. It will remain airtight until the protective seal is broken. 

Conclusion

Extraction is the final step in a long process to cultivate and care for cannabis trichomes. Without the right storage, much of the therapeutic value of the plant can be lost between harvest and extraction. Storage is a critical component of the extraction process, and the proper care and planning for storage will pay off in the quality of the final product. 

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FREQUENTLY ASKED QUESTIONS

What is the benefit of vacuum sealing?
Vacuum sealing removes oxygen from the container, which reduces the rate of oxidation. Oxidation degrades the therapeutic cannabinoids found in cannabis. Vacuum sealing helps with long term-preservation. 

What is heat induction sealing?
Heat induction sealers are created for the purpose of hermetic sealing, which is any type of sealing that makes a container airtight.  Heat induction sealers secure a foil laminate seal to the inside of a closure, creating an airtight environment for everything inside the container. This is the ideal environment for the long term storage of rosin, bubble hash, and even cannabis flowers. 

What happens if cannabis isn't properly stored?
Cannabis that's not properly stored is susceptible to rapid oxidation and degradation. It will likely dry out, become very brittle, and lose terpenes while cannabinoids are converted to less psychoactive and less therapeutic forms. 

What is volatility?
Terpenes are very volatile compounds, which means they will readily vaporize. Once terpenes vaporize they are considered lost. Improper storage will allow terpenes to vaporize, which means they won't provide any therapeutic value. 

What if you store cannabis while it's still wet?
Storing cannabis while it's still wet, either flowers or bubble hash, will invite microorganism growth which ruins cannabis and makes it unusable.