For growers of high value crops such as hemp and cannabis, the curing process is a critical step that adds additional quality to the finished product. But, what is curing? How is it different from drying? “Curing” and “drying” are two terms often used interchangeably and often misunderstood. One precedes the other. Buds are initially dried and then the second stage of drying, which is curing, can begin. Regardless if the buds were wet-trimmed or dry-trimmed, curing is the next step of the drying process.
At the curing stage, additional moisture is drawn out of the dried buds, and various chemical reactions are occurring which influence the final flavor profile, potency, color, and overall experience. The harsher aspects of consuming freshly-harvested flowers is subdued with slow and careful curing. Proper curing breaks down the harvested buds’ primary metabolites such as sugar and chlorophyll. Once curing is finished, the crop is ready to be sold, consumed, or stored for further processing or future utilization.
If buds are trimmed wet, they will need to be dried before beginning the curing process. During the entire process, it is critical to not over-dry the crop as this will lead to a loss of trichomes, and a flower that is very brittle to the touch.
Benefits of Curing
Curing affords numerous benefits to the end product and consumer. It brings out the full potential of the crop’s capabilities, bringing all of its best aspects to the surface for user enjoyment. The curing process allows for the gradual conversion of non-psychoactive cannabinoids into their active forms. This can result in a more balanced and nuanced set of effects when consuming the cured cannabis.
In addition to improved flavor, proper curing helps preserve the potency of cannabinoids like THC and CBD. Over-drying or inadequate curing can lead to the degradation of these compounds, Terpenes are preserved when buds are properly and slowly cured. A quick and hot drying results in poor quality product compared to robust flavor, aroma, and effects of properly cured buds.
In the curing process, chlorophyll breaks down. The loss of chlorophyll makes the user experience less harsh, and provides a smoother smoke. Cured cannabis tends to produce a smoother smoke, reducing irritation to the throat and lungs. This is due in part to the breakdown of compounds that contribute to harshness during the curing process. If buds are not properly cured and too much chlorophyll remains, they would have a vegetative taste, like lawn grass.reducing the overall effectiveness of the cannabis.
Curing also helps to eliminate the "fresh green" smell associated with newly harvested cannabis. It helps the harvested buds to develop a more nuanced and appealing aroma, indicating a well-cured product. Curing can also contribute to the development of a desirable texture in cannabis buds. Well-cured buds are often smoother, less harsh, and more visually appealing. This process also helps to maintain the integrity of the trichomes, which contain cannabinoids and terpenes.
For the professional or seller, curing cannabis extends product shelf life so that they can have a supply of fresh-tasting products even longer. It also means a supply that is resistant to mold or cannabinoid and terpene degradation if it is needing to be stored for a spell. In summary, curing is a crucial step in the cultivation process that significantly influences the quality, flavor, and effects of cannabis. It requires time and patience, but the benefits in terms of overall product quality are well worth the effort. But how exactly is this process done? Let’s take a look at how to properly cure your harvest and to achieve the highest levels of quality.
How to Cure Cannabis
Curing is the final step between drying and sending your product on to market (or enjoying it yourself). What do you need and how do you do it? There are a few different ways, but they all require essentially the same environment. A sealable vessel that either prevents light from entering or that is placed in a dark environment, that can prevent condensation and controls air moisture. This can be accomplished in very low tech ways, such as with glass jars or plant curing bags designed for the purpose. Other commercial containers and methods are on the market that work great as well.
The correct humidity range needs to be established. Here again, there is room for argument and different growers have differing opinions, but the outside ranges for curing are 55 to 65 percent humidity. There are some who keep humidity levels as low as 50, and there are also “sticklers” who insist on an exact humidity level, such as 62 percent, but until you have everything under control and have experimented with your setup, keeping the humidity between 55 and 65 percent will do the trick.
This should rehydrate the dried flowers just enough to improve their ultimate taste and smoothness, but still keep mold and diseases from appearing. Humidity levels below 55 percent will dry out terpenes, which are then irretrievable, even if humidity levels are raised. Keeping the range above 55 percent will promote better aroma, flavor, potency, and quality.
The ideal temperature range for curing is 60- 70 F (15.5-21 C). There is more consensus here. Most growers try to aim for right about 70 degrees F for curing, with the minority trying to maintain an environment closer to 60.
When setting up a curing room, make sure the room is within the required temperature and humidity range at all times and is in the dark. Lighting should only be used when checking the status of the curing process and then immediately turned off. Fans should be added to the space for good airflow, but avoid pointing them directly at the buds. This will help keep the air from becoming stagnant and will help with keeping the temperature and humidity levels even throughout the room. They will also help to prevent moisture and heat pockets around the buds which can form in still air.
Needs for Curing:
Airtight containment: Any container used must be sealable and airtight. Options include food-grade plastic sealable containers, breathable bags (designed for curing), airtight glass jars with lids, ceramic or metal jars, or even an entire room if all variables can be tightly controlled. Consider a product specially designed for airtight containment during curing, Grove bags. Grove bags are available in a range of sizes from ⅛ oz to 55 gallon drum liners. These tough, opaque pouches and bags help to keep your crop’s weight, preserve terpene profile, and prevent mold. They create an environment between 58-62 percent humidity, while diffusing unwanted gasses and water vapor.
Hygrometer: This measures temperature and humidity. You will need one in each container or bag where harvest is curing
A dark, temperature controlled environment: The stored harvest will begin to oxidize if exposed to UV light, so it needs to cure in near or total darkness. Trying to cure in extreme environments such as a wet basement or hot and dry attic will not serve your purpose and may render the entire batch unusable.
Steps for Curing:
- After your buds are trimmed and dried, put them into airtight containers. Fill each container about 3/4th full. Pack them in the container loosely, being careful not to compact or crush them. This allows for some amount of air in the container and around each bud, reducing the likelihood of mold or mildew developing. If using a hygrometer (recommended), place it in the container at this point and then seal the container(s).
- Check on your containers at least once daily for up to the first two weeks. When checking, remove the lids to allow for air exchange and moisture release, and inspect the buds for any signs of mold. Immediately get rid of any showing any signs of it as it will quickly spread to others within the same container. Lids should remain off for about five minutes before being resealed tightly. This process of releasing the stored air is referred to as “burping”. While inspecting the buds, they should start to become a little softer. This is because moisture from within the bud is being drawn out in the curing process. This is normal. If it does not happen, it is possible that your batch is over dried and you may need to add humidity to the containers.
- Adjust your humidity to achieve the 55-65 percent ideal moisture content. The hygrometer will let you know what the rate is within your container. If the humidity is too high, leave the lid off for several hours at a time before re-closing it. If it is too low, humidity packs can be added to reach desired levels.
- After the first week or two of daily checking and burping, burp your containers every few days and continue to monitor humidity levels. If your curing buds smell like ammonia upon opening, mold is starting and the container should be left off for up to a full day to dry them out again.
How do you know when the process is done? You will know the curing stage is done and your product is ready to go (or head to storage) by gently squeezing one of the buds. If everything was done properly and the cured buds retained much of their terpene load, squeezing will release a strong scent. Each strain has a slightly unique scent, but if you can describe it somewhere near “earthy” or “wood-like”, then you can consider the process a success.
Professional Products
Scaling up your operation? Going from a small to a medium sized or a medium to a large scale growing operation? Fortunately, there are a plethora of professional products and equipment on the market to aid in the curing process for larger scale curing.
Consider using the Integra Boost product line. These specially designed cards and packs will keep your crop perfectly between 55 and 62 percent humidity, depending on which product you select. Available individually or in multi-packs for medium to larger-scale growers, Integra products will absorb or release moisture to maintain ideal humidity levels. An indicator on the package will tell you when to replace the card or pack. They aren’t the only option though.
Boveda products are another great alternative. Working in the same general vein, Boveda humidity control packs will keep your curing process at 62%. Available in various strengths to accommodate different volumes of material, Boveda products also help to retain higher terpene and cannabinoid levels by creating a monolayer of purified water molecules that naturally coat trichomes to shield loss of flavor, aroma, and effect.
To take your curing process to the next level, consider a product like the Twister Cure Puck. This auto-curing device, and others like it, help to ensure perfect curing conditions automatically. It monitors vital indicators, and will automatically burp containers in a precise and controlled fashion to get maximum benefits from the curing process.
Monitor your curing process from afar. Utilizing IoT technology, the Twister Cure Puck will stabilize water activity, keeping your flower fresh and mold-free. There is no guesswork or manual adjustments with the Cure Puck. You will achieve improved burn, taste, aroma, and shelf life, all automatically and consistently.
The Twister Cure Puck has a back-up battery and 24/7 monitoring updates available via web app, so you can be sure even if you are away, that the process is being taken care of better than if someone were actually there. Get real time data, while reducing labor costs when you add a product like the Cure Puck.
If you aren’t quite ready for a top of the line product like the Cure Puck, there are still automated options for your curing process. Auto curing buckets can be bought or even created. These food grade, bpa-free, 5-gallon (or larger) buckets with gamma-seal lids can cure multiple pounds of harvest at once. Silicone tubing inserted into the bucket, capped with check valves serve as intake and exhaust ports. An air pump regulates this exchange, eliminating the need for manual burping of the container.
How Long to Cure
How long does it take to cure your harvest after drying? Like anything else multiple people do, there is a range of opinions on just the right amount of time for curing. One grocer may say ten days, another thirty days, and still another might say eight weeks. The dried product can keep for many months, and sometimes even years, but the quality starts to diminish after several weeks of curing.
An average length of time is around a month, with the caveat that many growers would say that is too long, with an almost equal number saying that is too short. The strain being grown should really dictate the length of time of curing. Most cannabis strains are ready for the market after four weeks of curing. There are, however, some cultivars that become more flavorful and aromatic after notably longer periods of time. Some strains even require up to six months of curing to reach their peak, but this is an exception to the normal length of time required for curing.
The environment that your harvest is being cured in and how often excess air is released will also play a part in determining how long to cure for. Also,if the buds were not sufficiently dry before going into the curing process, that will play a factor in the length of curing as well. Trial and error based on your particular curing process and strains will tell you when the ideal time to stop curing is.
If you have enough quantity, testing the flavor, aroma, and potency at various intervals will be informative. Conduct your first test after about two weeks, then once per week thereafter until you have found the “sweet spot”.
