The Significance of Loose-Leaf Vapor Temperature

Cannabis Connoisseurs
9 min readApr 15, 2020

There is no debate within the scientific or medical communities regarding the harm reduction and overall safety profile that is inherent in the vaporization of loose-leaf (“dry herb”) cannabis flower with regard to other types of inhalation — most notably, smoking. This fact regarding loose-leaf vaporization, however, can easily be misconstrued or misinterpreted by laypeople and experts alike for a variety of reasons.

“Cannabis ‘vaporization’ is a technique aimed at suppressing irritating respiratory toxins by heating cannabis to a temperature where active cannabinoid vapors form, but below the point of combustion where smoke and associated toxins are produced,” reported a peer-reviewed research study published in 2006.

Too often, patients and wellness professionals assume that all loose-leaf vaporizers are safe or “harm reducing,” posing fewer physical threats than the smoking of the herb. This is, unfortunately, untrue. Inferior quality hardware, tainted or contaminated cannabis (containing mold, mildew, fungi, or pesticides), and misuse of equipment all can result in “unsafe” cannabis vapor that poses a health threat to users.

Many characteristics of loose-leaf vaporization affect or potentially decrease this consumption avenue’s ability to deliver health-giving effects, including the hardware engineering employed to design or manufacture a vapor delivery device. Models built using inferior materials may involve a process called off-gassing during which potentially harmful and sometimes carcinogenic chemicals are emitted by parts of the vapor path (such as cheap plastics) when they are heated.

Often, these chemicals have been deemed by oversight bodies (such as the U.S. Food and Drug Administration) to be safe for ingestion (eating), but not necessarily for inhalation. Inhalation and ingestion are completely different metabolic pathways by which the cannabinoids and terpenes offered by herbs such as hemp enter the human body.

Why Vapor Temperature Matters

A critical element in determining the quality or medicinal value of the vaporization of loose-leaf cannabis flower is temperature. A variety of factors make the exact temperature at which cannabis flowers are vaporized a serious issue for medical and adult-use (“recreational”) consumers.

According to Leafly, the key to experiencing and enjoying loose-leaf vapor is the “array of flavors, aromas, and effects in cannabis” is the temperature at which the terpenes and cannabinoids contained therein are activated for inhalation. A challenge exists, however, for consumers and wellness professionals in terms of the exact temperature at which a particular sample of cannabis loose-leaf flower should be vaporized for maximum benefit.

Chasing Terpene & Cannabinoid Profiles

The subjective needs and efficacy of individuals mean that they must seek sometimes significantly different solutions to meet their medicinal needs or adult use goals. For example, a patient who suffers a disease based in inflammation, such as arthritis or fibromyalgia, should attempt to obtain cultivars (strains) of cannabis or hemp that provide ample volumes of the particular cannabinoids and terpenes known to be of value to their particular ailment, including its associated conditions and negative side effects.

To fully leverage the molecules trapped within the resin of cannabis loose-leaf flower, consumers must choose not only variants of the herb that contain sufficient amounts of the particular wellness molecules that best aid them, but also employ a reliable temperature-controllable vaporizer model that is capable of accurately achieving a wide range of temperatures.

Also, consumers and patients must possess a basic understanding of how the temperature of the airpath of the loose-leaf vaporizer in which they capture and deliver terpenes and cannabinoids to their lungs affects the overall bioavailability of their consumption. More about these important topics below.

Temperature Determines Activation

Different terpenes and cannabinoids feature markedly varying temperatures at which they become active and, thus, are of medicinal or therapeutic value to users when using a loose-leaf vaporizer. This makes the task of determining the optimal temperature at which to vaporize a particular sample of cannabis flower a relatively challenging task. The first goal of those wanting to engage in true harm reduction while vaporizing loose-leaf herbs such as cannabis should be to obtain a high-quality model vaporizer that offers as much control over temperature settings as possible (leading models often are controllable via a mobile app installed on a smartphone or tablet).

Consumers who own loose-leaf vaporizer models that feature user-adjustable temperature settings face the task of achieving a temperature (or, in more advanced models such as the DaVinci IQ2, a temperature profile) that activates the desired terpenes and cannabinoids.

Finding the Zone

The challenge becomes achieving a temperature that is sufficient to properly and fully vaporize the wellness molecules within the flower while simultaneously avoiding temperatures that are too great for greatest bioavailability (resulting in “burnoff” of the desired molecules). Many consumers, especially those driven by a “more is better” mindset, are ironically unaware that they may be applying vaporization temperatures that destroy the relatively delicate wellness molecules called terpenes and cannabinoids that they are seeking. This renders these healthy compounds useless, effectively decreasing the potency of a user’s medicine while simultaneously increasing its per-unit cost.

“Each of these compounds…boils at a specific temperature,” reported media outlet Leafly in a 2018 article entitled “The Secret to Unlocking Full Cannabis Flavors and Effects: Boiling Points.” “If you don’t heat [the cannabis] to that point, the biochemicals won’t activate. Go beyond the boiling point, though, and you’re likely to scorch [them] beyond recognition,” reported the article.

Understanding Grind Quality

In addition to temperature, it should be noted that the granularity, or grind size, of loose-leaf flower intended for vaporization, is of significant consequence to the quality of the resulting vapor. The fineness of the ground flower has a direct influence on the percentage of the terpenes and cannabinoids present in the resin of the plant that is vaporized and, thus, enters the lungs of users (a state in which they are considered “bioavailable”).

This is due to the manner in which vaporizers operate to generate a stream of warm air that is infused with a myriad of terpenes and cannabinoids (depending on what is present in the ground cannabis flower). Finer grind levels (smaller pieces of flower) better expose trichomes, the nearly microscopic and gooey resin-secreting glands that grow on the flowers of female cannabis plants. These sticky glands manufacture all of the cannabinoids and terpenes derived from the plant.

Trichome resin that is not exposed to a stream of heated air produced by a vaporizer is simply not vaporized and, thus, not made bioavailable. Unfortunately, this lack of mechanical efficiency that results in wasted effort and money is a common reality for millions of cannabis consumers.

Boiling Points

The molecules that deliver value in terms of health and wellness to consumers, including cannabinoids and terpenes, feature chemical boiling points. The boiling point of a molecule is the temperature at which it effectively vaporizes. Once suspended in vapor form, terpenes and cannabinoids can be transported along a vapor path in a mechanical device like a vaporizer and conveniently inhaled.

The boiling points of cannabinoids and terpenes cover a wide span. For example, a major terpene in cannabis and hemp — and the most common found in nature — is pinene. This aromatic terpene features a relatively low boiling point of 311° F (155° C). Caryophyllene oxide, another common terpene produced by cannabis and other plants, has a relatively high boiling point of 495° F (257° C) that is 60 percent greater than its sibling pinene.

A helpful exercise is the comparison of the boiling points of common terpenes to those of major cannabinoids. For example, tetrahydrocannabinol (THC) features a boiling point of 315° F (157° C), while cannabidiol (CBD) vaporizes within a range of 320° F (160° C) to 356° F (180° C).

Tetrahydrocannabivarin (THCV), the varin-version analog of THC that decreases appetite and may be helpful for those suffering from Type II diabetes and eating disorders, features a relatively high boiling point of 428° F (220° C).

Vaporization Research Studies

A variety of peer-reviewed research studies have been conducted regarding the harm reduction and health benefits of the vaporization of loose-leaf cannabis flower. The combustion of cannabis has been proven to deliver cancer-causing chemicals to the inhalation stream, including benzene, a potentially harmful molecule also produced by smoked tobacco.

A 2015 study entitled “No Smoke, No Fire: What the Initial Literature Suggests Regarding Vapourized Cannabis & Respiratory Risk” that was published in the Canadian Journal of Respiratory Therapy investigated “how to improve safety for the respiratory system in individuals who choose to use cannabis medicinally” by examining the data revealed in 12 other research studies.

The research reported how smoked cannabis features a history of use as an asthma therapy, including documented use in the 19th century and possibly earlier in history. “Cannabis served as an asthma treatment in the 1800s and, perhaps, in ancient times,” reported the study’s authors.

The study concluded that vaporization is safer and delivers far fewer potentially dangerous chemicals than combustion, which produces a long list of toxic byproducts. The researchers also reported that they found vaporization to produce markedly fewer overall chemicals than combustion.

The research reported that the vaporization of organic cannabis flower produced a gas that is overwhelmingly comprised of cannabinoids. “Only trace amounts of three other compounds were found,” wrote the researchers, “including the terpene caryophyllene and two other substances.” The study revealed that, in contrast, “smoke produced through the burned cannabis method…resulted in a much lower ratio of cannabinoids to overall gas space (12 percent of the total mass compared with 94.8 percent [when vaporized]), with 111 total detectable compounds.”

This study illustrated how the smoking of plants such as cannabis produces several potentially harmful substances that simply do not result from vaporized forms of cannabis flowers. “Five of these byproducts of combustion were known polynuclear aromatic hydrocarbons, organic pollutants with known toxic and carcinogenic effects,” reported the study. Concluded the researchers, “The findings suggest that vaporization reduces the delivery of toxic byproducts associated with the use of smoked cannabis.”

A 2014 human trial research study entitled “Experiences of Marijuana-Vaporizer Users” that was published in the journal Substance Abuse investigated the potential advantages of the vaporization of cannabis loose-leaf flower versus the combustion of smoking, including “potential harm-reduction advantages.”

The study, which involved 96 human test subjects, asked participants to identify any perceived advantages of vaporization versus smoking. Collectively, subjects identified four primary perceived advantages to vaporization of cannabis, including “perceived health benefits, better taste, no smoke [aroma], and more effect [greater potency] from the same amount of marijuana.”

The study’s authors concluded that vaporizers employed in the inhalation of cannabis flower are of significant harm reduction value to consumers. “Vaporizers seem to have appeal to marijuana users who perceive them as having harm-reduction and other benefits,” reported the study. “Vaporizers are worthy of experimental research evaluating [the] health-related effects of using them,” concluded the researchers.

A 2006 study entitled “Evaluation of a Vaporizing Device for the Pulmonary Administration of Tetrahydrocannabinol” that was published in the Journal of Pharmaceutical Sciences explored vaporization as a “feasible, non-smoked, rapid-onset delivery system” for “medicinal cannabinoids.”

Reported the study, “By changing…temperature setting…the vaporization of THC was systematically improved to its maximum, while preventing the formation of breakdown products of THC, such as cannabinol [CBN] or delta-8-THC.”

The research revealed that the use of a high-quality vaporizer involving no potential off-gassing results in roughly equivalent bioavailability of cannabinoids (such as CBD and THC) while at the same time providing harm reduction in the form of avoidance of respiratory damage due to toxins or carcinogens. “The final pulmonary uptake of THC is comparable to the smoking of cannabis while avoiding the respiratory disadvantages of smoking,” reported the study.

A 2000 study entitled “Marijuana Water Pipe and Vaporizer Study” that was conducted by California NORML and cannabis research pioneer Dr. Dale Gieringer investigated the difference between smoked and vaporized loose-leaf cannabis flower.

This study found that a particular model of vaporizer produced THC at a temperature of 392° F (200° C) while eliminating three measured toxins, including benzene (a known carcinogen), toluene, and naphthalene.

Reported the study’s authors, “Temperatures of around 392° F appear to be most efficient for vaporization. The potency of the cannabis in the study was on the order of 10–12 percent. Significant amounts of THC (around 5–6 percent) begin to be released at 356° F (180° C), with slightly more (7–8 percent) at 392° F (200° C).”

This research study concluded that vaporizer models that offer accurate temperature adjustment decreased or eliminated many of the unhealthy chemicals produced by the combustion of many plants, including cannabis and tobacco. “Carbon monoxide and smoke tars were both qualitatively reduced by the vaporizer,” reported the researchers.

Conclusion: Purchase Wisely

Consumers, patients, and wellness professionals seeking to reduce the potential harms associated with the smoking of herbs such as cannabis have begun to utilize high-quality loose-leaf vaporization devices. Research has revealed that such devices significantly decrease or eliminate the carcinogens and other toxins commonly produced through the combustion of cannabis flowers.

Use of loose-leaf vaporization devices that feature precision temperature selection and control enable consumers of loose-leaf cannabis flower to avoid potentially harmful chemicals while simultaneously optimizing the bioavailability of wellness molecules like terpenes and cannabinoids.

A good example of such a harm-reducing portable loose-leaf vaporizer is the new DaVinci IQ2. It features a vapor path that is fully void of any materials that might exhibit off-gassing into the airstream and ultimately enter a user’s lungs and brain. The two characteristics of harm-reducing vaporization and inhalation devices are 1) accurate temperature control and 2) a vapor path that is fully void of inferior materials that may potentially off-gas into the airstream.

Vaporization devices, especially many entry-level mobile models, often produce excessive temperatures, resulting in the destruction of relatively delicate terpene molecules.

Users must carefully research the specific terpenes and cannabinoids that meet their particular needs, including the boiling point temperatures of individual molecules. The trick becomes finding the sweet spot temperature (or set of staggered levels within a temperature profile) that best releases (activates) the wellness compounds within.



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