An overview of the cannabis drying and curing process
The curing of farmed cannabis is undertaken for broadly similar reasons to the curing of meats and other perishable foods.
By removing destructive bacteria, the cannabis curing process preserves organically based products for longer term storage. Like many cured meats, such as bacon and hákarl, users commonly find the taste of cannabis which has been preserved through curing to be more palatable than its fresher equivalent.
Why do we cure and dry cannabis?
By appropriately preserving each new crop of cannabis shortly after it is harvested, a producer can be certain that their harvest can be safely stored until it is sold. Freshly picked cannabis which is not dried or cured carries a greater risk of incurring mould, mildew or rot. Storing cannabis products which have not been correctly preserved or packaged in areas with high humidity levels will further accelerate the degradation process.
Some cannabis cultivation and production operations elide the necessary drying and curing processes from their product chains due to space and economic concerns: rather than setting aside a section of their facility to preserve the product before it is stored, these businesses would prefer to devote their entire operational space to storing unpreserved cannabis.
While in the short term this would appear to make economic sense, as it allows the producer more space for storage, in the long term it is deeply flawed; as the cannabis which is produced has a substantially shorter shelf life and is less strong than a correctly cured product – and, in the event of mould, can be hazardous or even toxic to the consumer.
Like all plant matter, cannabis begins to enter the process of degradation as soon as it has been harvested. Curing cannabis eliminates the bacteria and enzymes which cause the plant matter to break down; and in doing so, arrests the breakdown of terpenes and cannabinoids, both of which are essentially volatile compounds and, without intervention, would either break down into less active compounds or simply evaporate altogether.
How do we cure and dry cannabis?
To dry cannabis buds, their water content must normally be reduced to between 10% and 15%. This can vary according to the particular purpose of the finished product – experts recommend a final water content of 10% to 12% for cannabis which is to be smoked with tobacco, while product which is intended for use in a vaporiser may have water content between 12% and 15%. Gourmet users who prioritise flavour prefer buds with a water content as low as 8%, resulting in a purer flavour and an even burn.
In order to create an optimal product, the drying process must be slow and carefully regulated: rushed or inconsistent drying can result in a product which is dusty and fragile; or worse, if the drying process is not adequately completed due to haste and the product retains excessive moisture, the risk of mould and mildew increases.
It is typically considered best to dry a cannabis harvest in strictly controlled climate conditions: moderately cool drying rooms are preferred for better preservation of the highest possible levels of terpenes; however, at temperatures much below 15°C the product will retain excessive amounts of chlorophyll. This will have a detrimental effect on both the smell and taste. Judicious application of both heaters and coolers, as well as humidifiers and dehumidifiers, enable the producer to maintain a consistent level of temperature and humidity.
Curing can begin once the product has undergone the multi-day drying process: the dried cannabis is placed in sealed containers for retention of moisture and terpenes. These containers must be checked multiple times per day, to ensure that the cannabis is retaining an appropriate level of moisture – overly moist buds may need to return to the drying process for a period – and to change the air in the containers. Moisture inspections may be done through touch or using a hygrometer, which measures ambient humidity; producers who find their cannabis produces an ammonia-like odour at this stage must return it to the drying stage immediately, as this smell is an indication that excessive moisture is causing the plant to break down.
The curing process continues for at least one to two months, after which the air in the containers will need changing much less frequently. The final product may be stored in these containers for up to six months, or alternatively it may be vacuum packed for longer term storage and sale.
This article appeared in the second issue of Medical Cannabis Network which is out now. Click here to get your free subscription today.The curing of farmed cannabis is undertaken for broadly similar reasons to the curing of meats and other perishable foods.
- 1 Drying and Curing
- 1.1 Air Drying
- 1.2 Dry Ice Drying
- 1.3 Microwave and Oven
- 1.4 Heat Device Drying
- 1.5 Food Dehydrator Drying
- 1.6 Slow Cure
- 1.7 Sweat Cure
Drying and curing marijuana is a critical step in the growth process. During this stage you can lose, preserve, or cultivate odor, flavor, and potency. Odor and flavor must be carefully cultivated. The drying and curing process allow the plant to purge sugar and if desired to purge chlorophyll (although some have developed a taste for the chlorophyll in the plant).
Improperly dried and cured marijuana can lose almost all of its original potency and lower potency marijuana can be concentrated to slightly higher potency if handled properly. Four things reduce the potency of marijuana: exposure to light, heat, damage to the plant tissue, and air. Additionally, marijuana that is not dried and stored properly can contain too much moisture and grow mold (mould). It is important to remember that many rapid drying techniques will dry only the outside of a compact flower and that slow techniques like curing may be needed to draw that moisture to the surface.
The virtue in drying and curing as with all stages of marijuana cultivation is patience.
Air Drying Edit
Air Drying is probably the most popular method of drying marijuana. Air drying can be very well controlled. By controlling the amount of airflow, you control the speed of drying. A common technique is to suspend the plants upside down in a room with a circulating fan blowing (but not actually blowing on the plants themselves) in order to keep air moving. Another technique is to put the buds on a half open drawer or tray in a place with moving air. The further along in the drying process the more you close the drawer to reduce airflow.
A simpler way to dry the marijuana is to put the buds in a layer in a brown paper bag. This is simpler but faster and therefore the output is less desirable.
The speed in this process is a trade off. If you dry too fast then it will take longer to cure the marijuana properly. If you dry too slowly you will be exposing the marijuana to more air therefore reducing potency. Many growers shoot for about seven days drying time. If you are not going to cure the marijuana the plants should be dried until the stems snap easily rather than bend. If you are going to cure then you can begin with slightly more damp (but still mostly dry) marijuana.
Dry Ice Drying Edit
Because light, heat, and air all degrade potency someone came up with the idea of using a can or other container in a freezer or using a cooler to dry the marijuana using dry ice. Dry ice can be purchased at virtually any supermarket and is simply frozen carbon dioxide gas. In order to avoid injury you should avoid direct contact with your skin.
By using about the same amount of ice as marijuana you can dry your weed out without exposing it to air or light and certainly not heat! Simply lay down a layer of dry ice, put an insulating layer of breathable cloth over it like a cheesecloth or a simply kitchen towel. Then lay the buds spread out on top of the ice. Make sure there is a way for the gas to escape as the dry ice evaporates.
Dry ice never becomes liquid, it sublimates directly into a gas form and carries moisture away from your bud when it does. Once all the ice is evaporated your bud should be mostly dry. If not, put a little more ice in and repeat until it is dry.
Some experiments with this method have suggested that it may be better to remove the marijuana before the ice is completely evaporated, since some condensation will collect in the container adding moisture back (although this moisture will dry more quickly since it is not locked in the cells of the plant).
Unfortunately, this method causes the trichomes on your marijuana to fall off leaving you with a less potent product.
Microwave and Oven Edit
A microwave and an oven both dry marijuana using heat. You can cover bud between layers of paper towel in a microwave or use an oven on the lowest setting with the door cracked open to dry marijuana but heat will absolutely degrade the potency of your final output dramatically.
Heat Device Drying Edit
Professional heat fresh drying 100% preserves way, Drying in 2 hrs or less . Use heat from sterios or house sound system ect. Which generates perfect heat to dry fresh buds while its switched on. Rule 1: Put the fresh marijuana on top of the appliance heat. Rule 2: Get a plastic lid cover with air flow and lid cover the buds and wait one to two hours . Let the heat and cover lid do its magic trick.
Food Dehydrator Drying Edit
Food dehydrators can be used to dry marijuana along with most other materials but are not recommended for this purpose. Food dehydrators use the direct application of rapid air movement and in most models the application of heat to dry materials. As explained previously heat and air will degrade the psychoactive components in the marijuana such as THC.
Slow Cure Edit
Now that your initial drying is over you need to distribute the remaining moisture evenly through the bud because right now its all in the middle. You also want to remove some more of that moisture and the chlorophyll with it.
The traditional technique is the slow cure. With the slow cure you will put the material into a sealed container such as a glass jar or ceramic jar. Plastic containers aren’t recommended as much because they aren’t typically as air tight as glass jars or ceramic jars with sealed lids (think the type of jars you might put flour or sugar in). However, plastics that are inter-woven with EVOH (Ethylene-Vinyl Alcohol Copolymer) and have an aluminum metal exterior, provide identical air-tight properties to glass, if not better. Amateur growers recommend curing for a minimum of two weeks while seasoned growers recommend the longer the cure, the better the taste and aroma. You want to fill your storage device as much as possible, the less air the better. Keep the storage container at room temperature, never in an overly hot environment. Hot environments can cause the moisture to come out of the marijuana too quickly, which if left unchecked can cause mold or fungus to develop. Once a day for about the first week, with the storage device closed, gently shake the storage device around to move the buds(they will stick together, trapping the moisture between them) and then open the storage device, leaving it open for about 1-3 minutes, so that any excess moisture can evaporate, then re-close. After about 3 days in the storage device, it is recommended to combine (of the same strain) into a larger container, and close them. Some buds in the will cure faster than others, and there will be more moisture in some than in others. By rearranging the buds in, it equalizes the moisture. After the first week of opening once a day, and rearranging at least one time, you can go 2-3 days between opening, but make sure you still do this for at least 2 more weeks. After about 2-3 weeks, you will notice a significant change in the smell inside occurring. It will stop smelling like fresh cut grass or lawn clippings as much, and start smelling sweeter (or possibly spicier, depending on the strain). When you no longer can smell any hint of lawn clippings type of smell (some people also describe this as a putrid swamp smell) then you can be reasonably sure that the marijuana is cured and smokeable. The leaves on the buds maybe lighten up in color during this time also, though not always. The longer you cure it, however, the better the flavor and aroma will become, and typically the less harsh the smoke will be.
Once you’ve reached the ideal cure, do not open the storage device anymore unless you intend to consume the product, as opening will just continue to dry out the buds.
During the cure, the chlorophyll in the leaves turns to sugars, which is what gives the marijuana its taste and aroma. It also allows the trichomes (the sticky frosty stuff on the leaves and buds) a chance to ripen. Marijuana flowers ripen in much the same way as a tomato might. Think of a green tomato, you wouldn’t want to eat it (unless you actually like green tomatoes, but let’s assume you don’t) So you put the green tomato somewhere and leave it for a few weeks, and it turns red, soft, and edible. Bananas do this as well. No one likes green bananas, though they are still edible (just like marijuana is still smokeable) The difference in “ripe” marijuana is that the high will last longer than if you smoke it when it isn’t cured. Sometimes you may smoke uncured marijuana and only feel the effects for a very short time, but that same marijuana cured may last for hours when smoked.
Drying and curing marijuana are VERY different. If you use a “quick dry” method and then smoke it, expect to smoke garbage. You can still cure VERY dry marijuana, but it will be very crumbly when its cured.
Generally medicinal grade cannabis can be stored for approximately 6 to 12 months before any degradation is noticed as long as it is stored in completely airtight containers, in the dark. DO NOT STORE IT IN THE FREEZER, this could ruin your marijuana.
Gladware containers, Ziploc bags, and most “airtight” containers that do not have Ethylene-Vinyl Alcohol, inter-woven, with a metallized exterior (not to confused with the color “metallic”) other than glass and ceramic should be avoided, as they actually aren’t air tight as you think, and will cause quicker degredation of your finished product. Mason jars with air-tight lids are ideal for some, while many are transitioning to more advanced methods of storage that has been used in commercial packaging for years.
Sweat Cure Edit
This is often done in impoverished nations with large commercial crops and is similar to how tobacco is commonly cured. Pile your buds into a pile of alternating layers. Shift around the buds periodically. This will cure and brown the marijuana quickly but is using heat to do it. This technique will reduce potency and helps breed harmful fungus and bacteria. For these reasons it is not recommended. It is also common among Jamaican and Rasta culturistic curing techniques.Marijuana Cultivation/Curing Contents 1 Drying and Curing 1.1 Air Drying 1.2 Dry Ice Drying 1.3 Microwave and Oven 1.4 Heat Device Drying 1.5 Food Dehydrator ]]>