Air-drying cannabis requires the consideration of multiple factors, as changing one small aspect can alter the quality, taste, and level of cannabinoids and terpenes present in the dried plant. There are various ways to air-dry cannabis, including microwave-assisted hot air-drying, oven-drying, freeze-drying, and hang-drying (Al Ubeed et al., 2022). Each method and the present environment will impact the outcome of the final product.
The History of Drying Cannabis
Hang-drying cannabis is one of the earliest practices for drying cannabis, dating back to 2800 BCE when it was first documented in Emperor Shen Nung’s pharmacopeia (The University of Sydney, n.d.). Since then, the cannabis industry has discovered many ways to grow, cultivate, distribute, and consume cannabis, but hang-drying remains a reliable way to air-dry cannabis plants.
The practice of hang-drying is fairly simple in theory, despite the environmental factors this method must heavily consider. To use this method, you would first remove the extra stems from the cannabis plant and then either dry them on racks or hang them, as the method suggests, on string lines, wire cages, or static wires (Al Ubeed et al., 2022). This method for air-drying cannabis plants typically takes 14 days to achieve the desired results (Al Ubeed et al., 2022). However, the process of hang-drying cannabis is a very complex and time-consuming method.
Factors to Consider When Hang-Drying Cannabis
The environmental conditions of drying cannabis will be a significant factor to consider before you begin drying. It’s recommended to have postharvest strategies planned out before cannabis has even been planted for growth (Drotleff, 2022).
In coastal regions where cannabis growth and consumption is legal, like California, Oregon, and Washington state, drying cannabis can be challenging to achieve rapidly due to the “marine layer influence, which causes elevated nighttime humidity and, in some areas, fog. It is this marine layer influence that is responsible for mold and/or mildew proliferation in some cannabis,” (Morrow, 2020). Fall and winter would be the best time to dry cannabis in these coastal regions.
In drier regions such as Arizona, Colorado, and Nevada, there is not nearly as much concern for drying cannabis, but each has some environmental factors to consider. Arizona and Nevada are arid regions with extremely low humidity year-round, aside from Arizona’s monsoon season, which occurs between June and September. They also have much higher temperatures than the coastal regions, reaching as high as 115-120°F, making the drying process more manageable and mold and mildew growth slightly less concerning (Morrow, 2020).
In temperate regions like Colorado, where all four seasons can be experienced, there can be more difficulty in drying and curing cannabis plants since the weather can be less predictable than in coastal states.
Likewise, the elevation in Colorado is much higher than in other regions, reaching more than 5,000 feet in some areas. This means “temperatures can range from sub-0°F in winter to well over 100°F in summer. In winter, in one 24-hour period, it can range from subzero and snowing with 0 percent humidity at night to 75°F with 60 percent humidity during the midday as the snow melts in the sunshine” (Morrow, 2020).
The region you’re cultivating cannabis should also be considered when deciding how to hang dry cannabis. In areas with high humidity levels, “it’s advisable to break plants into individual branches or allow more space between plants to reduce the potential for mold.” Meanwhile, “dry or arid regions might require whole-plant drying to slow the drying process,” and reduce terpene loss (Drotleff, 2022).
Considering the environment is the most important factor when cultivating cannabis and using a climate-controlled room is best for achieving desired results. The cannabis needs to dry in an environment that is not too hot or cold and in a well-ventilated room with access to fresh, filtered air. No exact temperature or set humidity will work for everyone because of all the environmental variables. However, changing and controlling the room’s temperature and humidity levels are essential when hang-drying cannabis (Morrow, 2020).
When temperatures are too cold with improper airflow, cannabis retains high levels of chlorophyll and develops an off taste and smell comparable to fresh-cut grass or hay. Eliminating humidity also won’t produce desired results because although you would dry cannabis faster, you would also rapidly reduce the plant’s terpenes (Morrow, 2020).
Typically, monoterpenes evaporate first and are the primary terpenes to evaporate during drying. The goal when drying cannabis is to remove moisture as fast as possible without losing excessive amounts of terpenes. The outside of the plant will dry first, so it will be necessary to extract humidity from its core without over-drying the outside. Many people do this by rehydrating the plant once it’s dried by placing them in sealed containers. The containers are then checked multiple times a day and given fresh air. Once the plant is uniform in moisture again, they are rehung or placed back on drying racks. This process repeats until the desired moisture levels are achieved (Morrow, 2020). Depending on the environment and the amount of cannabis hang-drying, the entire drying process can take three to four weeks (Drotleff, 2022).
Benefits of Hang-Drying Cannabis
Hang-drying cannabis can be considered a traditional method as it’s the earliest drying method, but it is also effective at keeping the integrity of the original, fresh plant intact. In a study published by the Journal of Natural Products, hang-drying did not affect “the qualitative composition of the oil” or the distinct odor (1996). This indicates that when closely monitored, hang-drying cannabis maintains the original quality, taste, odor, and cannabinoid and terpene retention.
Things to Consider When Hang-Drying Cannabis
However, a lot can happen in the few weeks it takes to dry. Hang-drying requires daily inspection and proper maintenance of the plants. It also has a significant potential for mold growth if not adequately monitored due to its lesser controlled conditions, making it a complex and time-consuming method for drying cannabis (Al Ubeed et al., 2022). Hang-drying is labor-intensive compared to other methods and can leave significant room for crop damages to occur, “which is why few large-scale commercial growers” choose this method.
Although a complex method, hang-drying cannabis has been a tried-and-true method for drying and preserving cannabis plant compounds, it also requires extra time and attention to detail; therefore, this method may not be for everyone.
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Al Ubeed, H. M. S., Wills, R. B. H., & Chandrapala, J. (2022, March 6). Post-harvest operations to generate high-quality medicinal cannabis products: A systemic review. Molecules (Basel, Switzerland). Retrieved January 31, 2023, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8911901/#B77-molecules-27-01719
Cannabis drying methods: An overview. Steep Hill Illinois. (2023, January 25). Retrieved January 30, 2023, from https://www.steephillil.com/post/cannabis-drying-methods-an-overview
Drotleff, L. (2022, September 14). How to dry and cure cannabis to ensure quality, shelf life. MJBizDaily. Retrieved February 9, 2023, from https://mjbizdaily.com/how-to-dry-and-cure-cannabis-to-ensure-quality-shelf-life/
History of cannabis. The University of Sydney. (n.d.). Retrieved January 30, 2022, from https://www.sydney.edu.au/lambert/medicinal-cannabis/history-of-cannabis.html
Morrow, K. (2020, January). Master the art of drying and curing cannabis. Cannabis Business Times. Retrieved February 9, 2023, from https://www.cannabisbusinesstimes.com/article/master-the-art-of-drying-curing-cannabis/
Ross, S. A., & ElSohly, M. A. (1996, January 22). The Volatile Oil Composition of Fresh and Air-Dried Buds of Cannabis sativa. ACS Publications. Retrieved February 9, 2023, from https://pubs.acs.org/doi/10.1021/np960004a