Is 60/60 really the best way to dry cannabis? When learning how to dry cannabis, growers have traditionally relied on the 60/60 method, drying flower at roughly 60°F and 60% relative humidity, for a slow, controlled dry. But is it actually the safest or most effective way to preserve quality? In this article we explore why 60/60 became the traditional drying target, the relationship between temperature, humidity, moisture loss, and microbial growth, terpene preservation, and what the scientific research actually tells us about drying.
Key Takeaways
• Why 60°F/60% RH became the traditional drying target.
• The relationship between temperature, humidity, moisture loss, and microbial growth.
• Whether a long, humid dry may increase mold/pathogen risk.
• Why terpene preservation is the primary argument for keeping drying temperatures low.
• What scientific drying research actually tells us.
• Sharkmouse Farms’ alternative approach using warmer temperatures and lower RH to shorten drying time.
• Whether faster drying could preserve quality by reducing time flower remains wet and exposed to oxygen.
What Is the 60/60 Cannabis Drying Method?
The 60/60 cannabis drying method means drying freshly harvested cannabis at roughly 60°F (15.6°C) and 60% relative humidity (RH), typically in darkness with gentle air circulation. The goal is to create a slow, controlled dry that allows moisture to leave the flowers gradually while cooler temperatures help limit the loss of volatile aromatic compounds like terpenes. The method is simple, repeatable, and has become one of the most widely accepted rules in cannabis cultivation. However, while 60/60 has been used successfully for decades, there is limited evidence that these exact conditions are the optimal way to dry.
Why Slow Drying Became Synonymous With Quality
For as long as I have been cultivating cannabis, 60/60 has been the rule of thumb. It has been passed down from grower to grower with the idea that drying flower slowly at low temperatures preserves more terpenes and ultimately produces better-tasting, smoother-smoking cannabis. That advice didn't come out of nowhere. Long before 60°F and 60% RH became the numbers growers repeated, influential cultivation authors such as Jorge Cervantes were recommending cool, slow drying. In 2004, Cervantes advised growers to dry cannabis at roughly 59–70°F and 50–60% RH, while later cultivation guides continued to associate slow drying with improved flavor and a smoother smoke.
The Problem With 60/60
Freshly harvested cannabis contains a lot of water, and removing that water slowly isn't necessarily without risk. Dense cannabis flowers can retain moisture deep within the inflorescence even as the exterior begins to dry. Cannabis can also enter the drying room carrying fungal spores and other microorganisms acquired during cultivation. After harvest, temperature, humidity, airflow and drying rate all influence how quickly moisture leaves the flower. The longer cannabis remains at elevated moisture and water activity, the longer certain microorganisms, like mold, may have conditions favorable for growth.
This doesn't mean that 60/60 causes mold, or that cannabis cannot be dried safely using the method. It means that extending drying time isn't automatically beneficial. If we're going to evaluate whether a slower dry produces better cannabis, we also have to consider how long the flower remains in a moisture range capable of supporting microbial activity. And that requires looking at something 60% room humidity alone can't tell us: the water activity of the flower itself.
Relative Humidity Isn't the Same Thing as Water Activity
When drying cannabis, relative humidity tells us about the air in the drying room, while water activity (aw) tells us how much water within the flower is available to support microbial growth and chemical reactions. The two are related, but they aren't interchangeable. Once cannabis has been sealed and allowed to reach equilibrium, the relative humidity of the surrounding air can be used to estimate water activity. But cannabis actively drying in a room at 60% RH does not necessarily have a water activity of 0.60. That's an important distinction: a hygrometer tells us what's happening in the room. Water activity tells us more about what's happening in the flower.
What Food-Safety Science Can Teach Cannabis Growers
Food-safety science has long recognized that controlling water activity and the amount of time a product remains at elevated water activity is important for limiting microbial growth and improving shelf stability. The same principle is relevant when drying cannabis. Cannabis isn't food, but it is a harvested biological material that can carry bacteria, yeasts and molds into the drying room. This is reflected in regulated cannabis markets, where finished flower is routinely tested for microbial contaminants such as Aspergillus species, Salmonella, E. coli, and total yeast and mold, although specific requirements vary by jurisdiction. This doesn't mean that drying at 60/60 is inherently unsafe. It means that microbial control deserves consideration alongside terpene preservation and drying speed when deciding how we dry cannabis.
My Experience With Botrytis Changed How I Think About Drying
The first time I dealt seriously with Botrytis was during a winter greenhouse grow, when temperatures were cool and humidity was consistently high. After watching bud rot develop in my flowers, I went down the rabbit hole learning everything I could about the pathogen. I learned that Botrytis spores can spread through air and water and may be present long before we see visible signs of infection. They can take advantage of damaged or susceptible plant tissue, and cool, humid conditions can favor disease development. That's when I started looking differently at the advice I had always followed after harvest. I had just spent weeks fighting a fungal pathogen favored by cool, moist conditions, yet the conventional recommendation was to harvest those moisture-rich flowers and dry them slowly at around 60°F and 60% RH.
It doesn’t mean 60/60 was causing Botrytis, but it made me question the logic of deliberately extending the amount of time a potentially contaminated flower remained wet. Was the slowest possible dry really the best way to preserve quality, or could moving through that high-moisture stage more quickly actually protect it? That experience changed the way I think about drying. Instead of assuming a longer dry automatically produces better cannabis,
If Faster Drying Reduces Microbial Risk, Why Do We Dry Cannabis So Slowly?
If getting moisture out of harvested cannabis more quickly can reduce the time it spends in conditions favorable to microbial growth, why has the industry traditionally favored a slow dry? A major reason is terpene preservation. Growers have long been taught that drying cannabis slowly at cooler temperatures helps retain the volatile compounds responsible for much of the flower's aroma and flavor. So, to understand whether faster drying actually sacrifices quality, we first need to understand what we're trying to preserve.
What Are Cannabis Terpenes?
Terpenes are volatile aromatic compounds that contribute significantly to the smell and flavor of cannabis. Compounds such as myrcene, limonene, pinene and linalool help create the distinctive aroma profiles we associate with different cultivars. Not all terpenes behave the same way. They have different physical properties and degrees of volatility, meaning some are more easily lost during postharvest handling than others.
In a 2024 study performed by Simon Fraser University, researchers compared a traditional 60/60 drying method to a controlled atmosphere drying chamber with 10% humidity and 60F. The traditional method took 14 days to dry while the controlled atmosphere with far lower humidity took 6 days, the study found no difference in terpene preservation but a significant increase in mold infestation of A. alternata and botryitis in the cannabis dried traditionally. That gives growers a legitimate reason to care about how cannabis is dried.
Why Temperature Matters for Terpene Preservation
One of the strongest arguments for drying cannabis at cooler temperatures is terpene preservation. Because terpenes are volatile, they can escape from the flower and enter the surrounding air during drying and they don't need to reach their boiling point for that to happen. Even at relatively low temperatures, volatile compounds exert vapor pressure, allowing molecules to move from the flower into the air. As temperature increases, vapor pressure generally increases as well, which can accelerate the loss of some volatile compounds.
But temperature isn't acting alone. Air exchange can carry those compounds away, oxygen can contribute to chemical changes, and physical handling can damage trichomes containing many of the compounds we're trying to preserve. Different terpenes also behave differently, so there isn't one temperature at which cannabis suddenly begins "losing its terpenes." Research on cannabis and hemp supports the broader principle that drying conditions can alter terpene profiles, with temperature and drying method influencing which compounds are retained or lost. If a longer drying period doesn't necessarily preserve more terpenes, is there actually a quality advantage to keeping cannabis wet for 10–14 days when it can reach an appropriate moisture level much sooner?
What the Research Says About Faster Cannabis Drying
Research confirms that increasing temperature can dramatically shorten drying time but there is a tradeoff. In his 2020 research at Dalhousie University, Sai Kiran Reddy Challa tested hemp flower using several drying temperatures and methods, measuring drying time along with CBD, terpene content and color. As temperature increased, drying time decreased substantially. One stepwise drying treatment reduced drying time by approximately 90% compared with the 32°C (90°F) control.
But faster wasn't automatically better. Temperatures above 40°C (104°F) significantly reduced total terpene content, with the greatest losses occurring at the highest temperatures. Total CBD, however, was not significantly affected by increasing drying temperature, although higher temperatures increased the conversion of CBDA to CBD. Challa also found no significant color change at the higher temperatures tested. This doesn't tell us that cannabis should be dried at 104°F—or anywhere close to it. What it does demonstrate is that drying temperature can dramatically change how quickly moisture leaves the flower, while different components of quality respond differently to that change.
That leaves a large middle ground between a prolonged 60°F/60% RH dry and the high-temperature drying treatments used in research. And that's exactly where growers like Sharkmouse Farms are experimenting.
Seedsman Community AMA with Sharkmouse Farms
Sharkmouse Farms Doesn't Dry at 60/60
While researching this question, I sat down with Sharkmouse Farms, an experienced cannabis cultivator known for challenging conventional growing practices and testing techniques in his own garden rather than simply accepting industry rules as fact. One of those rules is 60/60. Sharkmouse doesn't follow the traditional 60°F/60% RH approach. Instead, he uses a faster drying process designed around moving moisture out of the flower efficiently while maintaining the quality, aroma and consistency of the finished product.
His method is based on years of hands-on cultivation experience rather than a controlled scientific study, so it shouldn't be treated as proof that 60/60 is wrong. But his results raise many of the same questions emerging in postharvest cannabis research: How slowly does cannabis actually need to dry, and what are we gaining, or potentially risking, by extending that process?
https://youtu.be/vZo-NLBx_4k?si=Se-zyIlFWJHehwb-
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Is 60/60 Really the Best Way to Dry Cannabis?
So, is 60/60 really the best way to dry cannabis? The answer appears to be: not necessarily. There's a reason 60°F and 60% RH became a trusted starting point. Cool temperatures can help protect volatile compounds, and a controlled drying environment is certainly preferable to drying cannabis too hot or too quickly without understanding the consequences. But the research also doesn't support the idea that cannabis needs to spend 10–14 days drying at exactly 60/60 to produce high-quality flower. Faster drying methods have successfully shortened the process without necessarily sacrificing total terpene content, while also reducing the amount of time moisture-rich flower remains vulnerable to microbial growth.
What seems increasingly clear is that there probably isn't one perfect temperature, humidity or drying duration for every harvest. Cultivar, flower density, starting moisture, airflow and the actual moisture condition of the flower all matter. Rather than asking whether 60/60 is right or wrong, perhaps the better question is: What conditions get this particular flower safely and efficiently to the moisture level we want while preserving as much quality as possible?
And there's still an even bigger question: How do different drying and curing methods affect the way cannabis actually smokes? That's what I'm digging into next. Next month, I'll be sitting down with Dr. Allison Justice, cannabis researcher and founder of The Hemp Mine, to discuss her postharvest research and the Science of Smokability project, including what researchers are learning about water activity, drying, curing, chemical composition and how those variables may ultimately influence the smoking experience..
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References:
• Challa, S. K. R. (2020) — drying kinetics, temperature, terpenes, cannabinoids, color.
• Ross, S. A., & ElSohly, M. A. (1996) — fresh vs. air-dried cannabis volatile composition.
• Bueno, J., et al. (2020) — terpene preservation.
• Milay, L., et al. (2020) — postharvest storage stability; use only where applicable.
• Birenboim, M., et al. (2024) — cultivar-specific medicinal cannabis drying; controlled-atmosphere vs. traditional drying, drying duration, terpene retention, cannabinoids, color, and fungal contamination.
• U.S. FDA Water Activity guidance — aw/microbial-stability concepts; label clearly as food science, not cannabis-specific guidance.