A
vaporizer (or
vapouriser) is a device used to extract and deliver via
inhalationInhalation is the movement of air from the external environment, through the air ways, and into the alveoli.Inhalation begins with the onset of contraction of the diaphragm, which results in expansion of the intrapleural space and an increase in negative pressure according to Boyle's Law...
the active ingredients of
plantPlants are living organisms belonging to the kingdom Plantae. They include familiar organisms such as trees, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The scientific study of plants, known as botany, has identified about 350,000 extant species of plants, defined as seed plants,...
material, commonly
cannabisCannabisalso known as marijuana or marihuana, and ganja , among many other namesrefers to any number of preparations of the Cannabis plant intended for use as a psychoactive drug...
,
tobaccoTobacco is an agricultural product processed from the leaves of plants in the genus Nicotiana. It can be consumed, used as an organic pesticide, and in the form of nicotine tartrate it is used in some medicines. In consumption it most commonly appears in the forms of smoking, chewing, snuffing, or...
, or any of many other herbs or blends (phyto-inhalation; see also:
aromatherapyAromatherapy is a form of alternative medicine that uses volatile plant materials, known as essential oils, and similar aromatic compounds from plants, for the purpose of improving a person's mood, cognitive function or health. Preliminary scientific evidence is growing in all these areas. An...
).
VaporizationVaporization of an element or compound is a phase transition from the liquid phase to gas phase. There are two types of vaporization: evaporation and boiling....
is an alternative to
smokingSmoking is a practice where a substance, most commonly tobacco, is burned and the smoke tasted or inhaled. This is primarily practised as a route of administration for recreational drug use, as combustion releases the active substances in drugs such as nicotine and makes them available for...
. Rather than
burningCombustion or burning is a complex sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat or both heat and light in the form of either a glow or flames, appearance of light flickering.Direct combustion by atmospheric oxygen is a reaction...
the herb, which produces irritating,
toxicToxicity is the degree to which a substance is able to damage an exposed organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell or an organ , such as the liver...
, and
carcinogenA carcinogen is any substance, radionuclide or radiation that is an agent directly involved in the promotion of cancer or in the increase of its propagation. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes...
ic by-products, a vaporizer heats the material in a partial vacuum so that the active compounds contained in the plant boil off into a
vaporA vapor or vapour is a substance in the gas phase at a temperature lower than its critical temperature....
. No combustion occurs, so no smoke or taste of smoke is evident. The vapor ideally contains virtually zero particulate matter or
tarTar is the common name for the resinous partially combusted particulate matter produced by the burning of tobacco and other plant material in the act of smoking. Tar is purportedly the most destructive component in habitual tobacco smoking, accumulating in the smoker's lungs over time and damaging...
, and significantly lower concentrations of noxious gases such as
carbon monoxideCarbon monoxide is a colorless, odorless and tasteless gas, yet very toxic to humans. It consists of one carbon atom and one oxygen atom, connected by a covalent double bond and a dative covalent bond...
. Also, less chance of flames occur. The vapor is extracted in various forms of extraction chambers then inhaled directly through a hose or pipe including vapor-specific vaporization water tools for highest activity, or stored for subsequent inhalations in a container such as a bag or jar. With little to no smoke produced, cooler temperatures, and less material required to achieve a given level of effect, the irritating/harmful effects of smoking are greatly reduced or eliminated, along with
second hand smokePassive smoking is the inhalation of smoke, called secondhand smoke or environmental tobacco smoke , from tobacco products used by others. It occurs when tobacco smoke permeates any environment, causing its inhalation by people within that environment...
, by using a vaporizer.
In comparison to other drug delivery methods such as ingestion, vaporization offers the advantages of rapid onset of pharmacological effect, direct delivery into the bloodstream (via the lungs), and more precise
titrationTitration is a common laboratory method of quantitative chemical analysis that is used to determine the unknown concentration of a known reactant...
such that the desired level is reached and not exceeded, enabling consistent and appropriate dosage.
Classification
Precise vaporizers use an electric heating element, often featuring
thermostatA thermostat is a device for regulating the temperature of a system so that the system's temperature is maintained near a desired setpoint temperature. The name is derived from the Greek words thermos "hot" and statos "a standing"...
ic temperature control. High-end models may cost several hundred U.S. dollars.
Broadly, vaporizers may be classified by how they heat the substance:
- By thermal conduction
- By convection
Convection is the movement of molecules within fluids . Convection is one of the major modes of heat transfer and mass transfer...
- By thermal radiation
Thermal radiation is electromagnetic radiation emitted from the surface of an object which is due to the object's temperature. An example of thermal radiation is the infrared radiation emitted by a common household radiator or electric heater. A person near a raging bonfire will feel the radiated...
In
conduction heating, the substance is placed on a metal plate that is then heated to release the active constituents. Conduction vaporizers were the first type to appear on the market, and are still in production.
In
convection heating, the substance itself never touches a heating element. Instead, hot air passes through it, heating it rapidly, and allowing the release of the active constituents. This method of heating releases more active constituents than conduction heating.
- Many convection vaporizers use a tube (called a "whip") through which the user inhales the vapors. Some vaporizers have a bag or balloon attachment; vapor is blown into the bag, and the user detaches the bag and inhales the contents. Attachments can be placed between the vaporizer or bag and the user's mouth to cool the vapor with water or ice.
- Convection vaporizers are either forced air types which actively blow air through the heating element and herbs, or passive types, where the user inhales the air without help of a fan or pump. Most vaporizers today use the convection principle, including heat guns, "wood box" types, and nearly every higher end vaporizer on the market today.
In
radiation heating, the substance is subjected to bright light. The substance absorbs radiant energy and its temperature rises. Radiation vaporizers are rare, but capable of duplicating the performance of convection vaporizers. A magnifying glass and a long flexible drawtube on a bright, sunny day can, with care and practice, act as an adequate radiation vaporizer system.
Vapor quality
Few vaporizer studies or reviews have really addressed the quality of the vapor extracted and delivered; instead, focus has generally been on the mode of usage of the vaporizer. When one considers that there are at least 60 pharmacologically-active compounds in cannabis and that the aromatic terpenoids begin to vaporize at 126°C, but the more bio-active
cannabidiol (CBD)Cannabidiol is a psychoactive cannabinoid found in Cannabis. It is a major constituent of the plant, representing up to 40% in its extracts.CBD alone is not intoxicating, but displayed sedative effects in animal tests...
,
Cannabinol (CBN)Cannabinol is a non-psychoactive cannabinoid found in Cannabis sativa and Cannabis indica. It is also a metabolite of tetrahydrocannabinol . CBN acts as an agonist at the CB
1 and CB
2 receptors, but with lower affinity in comparison to THC.- External links :* Compounds found...
, and
delta-9-tetrahydrocannabinol (THC)The acronym THC has several possible meanings:* Tetrahydrocannabinol, the main active chemical compound in Cannabis* Toronto Hemp Company, the world's largest Hemp and Cannabis Culture store, located in Toronto, Canada....
do not vaporize until near their respective
flash pointThe flash point of a volatile liquid is the lowest temperature at which it can vaporize to form an ignitable mixture in air. Measuring a liquid's flashpoint requires an ignition source. This is not to be confused with the auto-ignition temperature, which requires no ignition source. At the flash...
s: CBD 206.3°C (406.34°F), CBN 212.7°C (414.86°F), THC 149.3°C (300.74°F) then it becomes apparent that the only way to get a full spectrum vapor inhalation is to extract and deliver rapidly from a small sample at a time. Because most commercial vaporizers are slow in extraction and delivery, the vapor inhaled is first aromatic, but only minimally active; and then as the plant material temperature rises, the vapor becomes increasingly bio-active, but minimally aromatic, because most of the aromatics have already been released. This problem is addressed in the vaporization "tool" based "systems" by use of a sequential venturi effect for more rapid extractions via a vaporization chamber bowl and vaporization heat wand or heat gun approach. With these approaches many common pipes can be simply modified enabling the delivery of broader spectrum vapor preferred by many users and superior in concentration, consistency, and aromatic density due to the increased rate of extraction and smaller sample size.
Most vaporizers deliver dry, warm vapor that can irritate the throat and upper airway tree. By running the vapor through water and/or past ice to moisture condition and cool prior to delivery irritation of the throat and upper airway can be reduced or eliminated. Raising the temperature so pyrolysis products like nitrosamine are present, is known to increase risk for cancer in exposed oral and airways epithelium, among other health effects of tobacco. A properly used vaporizer should never allow this to happen; however, many smokers making the transition to vaporization will make this mistake. Smoking means
pyrolysisPyrolysis is the chemical decomposition of condensed organic substances by heating. The word is coined from the Greek-derived elements pyro "fire" and lysys "decomposition"....
, so tar and noxious gas from cannabis
combustionCombustion or burning is a complex sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat or both heat and light in the form of either a glow or flames, appearance of light flickering.Direct combustion by atmospheric oxygen is a reaction...
are absent in properly temperature constrained vapor. In addition, THC is a powerful expectorant, so the cilia, cough and other healthy airways defense mechanisms are activated, cleaning out any inhaled material. Vaporizers or vaporization "tool" based systems that feature rapid extraction and delivery combined with water and/or ice cooling and conditioning of the vapor deliver the best of all: clean, concentrated, cool, and moisturized vapor for maximized bio-activity and minimized impact.
Scientific studies of cannabis vaporiser usage
All studies have found the release of harmful constituents dramatically reduced or completely eliminated. Substantial reductions were also found for the M1-volatizer. However, a 1996 study including two simple vaporizers still found ten times more tar in the vapor than THC, although this was nevertheless up to a 30% improvement compared to the best alternative smoking method.
The most recent study, published in the Journal of Psychopharmacology in May 2008, investigated the acceptability and usefulness of intrapulmonary THC administration using a
Volcano VaporizerThe Volcano Vaporizer is a vaporizer machine consisting of a conical heater base with controls for manipulating the airflow and temperature. It is used for aromatherapy, smokeless ingestion of cannabis or other herbs, and culinary preparation. The air collection system consists of a heatproof bag,...
and pure THC instead of cannabis. Rising doses of THC (2, 4, 6 and 8 mg) were administered with 90 minutes intervals to twelve healthy males. Very low between-subject variability was observed in THC plasma concentrations, characterising the vaporizer as a suitable method for the administration of THC.
In 2007, a study by
University of California, San FranciscoThe University of California, San Francisco is one of the world's leading centers of health sciences research, patient care, and education. UCSF's medical, pharmacy, dental, nursing, and graduate schools are among the top health science professional schools in the world. The UCSF Medical Center is...
published in the Official Journal of the American Academy of Neurology examined the effectiveness of a vaporizer that heats cannabis to a temperature between and degrees and found:
In 2006, a study performed by researchers at
Leiden UniversityLeiden University , located in the city of Leiden, is the oldest university in the Netherlands. The university was founded in 1575 by Prince William of Orange, leader of the Dutch Revolt in the Eighty Years' War. The royal Dutch House of Orange-Nassau and Leiden University still have a close...
, tested a vaporizer with preparations of pure THC and found that:
When using plant material (crude flower tops), besides THC, several other cannabinoids as well as a range of other plant components including
terpenoidsTerpenes are a large and varied class of hydrocarbons, produced primarily by a wide variety of plants, particularly conifers, though also by some insects such as termites or swallowtail butterflies, which emit terpenes from their osmeterium....
were detected in the plant material. However, using pure THC in the Volcano vaporizer, no degradation products (delta-8-THC (D8-THC),
cannabinolCannabinol is a non-psychoactive cannabinoid found in Cannabis sativa and Cannabis indica. It is also a metabolite of tetrahydrocannabinol . CBN acts as an agonist at the CB
1 and CB
2 receptors, but with lower affinity in comparison to THC.- External links :* Compounds found...
(CBN), or unknown compounds) were detected by
HPLCHigh-performance liquid chromatography is a form of column chromatography used frequently in biochemistry and analytical chemistry to separate, identify, and quantify compounds...
analysis. Also, a substantially larger fraction of the THC was delivered to the vapor by using pure THC.
Analysis of the vapor from the vaporizer found that using multiple passes it delivered 36%–61% of the THC in the sample. A more recent study using pure cannabinoid preparations achieved a maximum of 54%. For comparison, studies of cannabis cigarettes smoked via a smoking machine under varying conditions of puff duration and air speed found very similar efficiencies of 34% to 61%. Consequently, users can achieve the desired effect with a similar amount of material as when smoking.
In a 2001 study testing a device called the M1 Volatizer, the researchers found that "it is possible to vaporize medically active THC by heating marijuana to a temperature short of the point of combustion, thereby eliminating or substantially reducing harmful smoke toxins that are normally present in marijuana smoke." The M1 Volatizer, produced THC at a temperature of , while eliminating three measured combustion products,
benzeneBenzene, or benzol, is an organic chemical compound with the molecular formula C6H6. It is sometimes abbreviated Ph–H. Benzene is a colorless and highly flammable liquid with a sweet smell and a relatively high melting point...
,
tolueneToluene, also known as methylbenzene, or Toluol, is a clear water-insoluble liquid with the typical smell of paint thinners, reminiscent of the related compound benzene. It is an aromatic hydrocarbon that is widely used as an industrial feedstock and as a solvent...
and
naphthaleneNaphthalene, also known as naphthalin, or antimite and not to be confused with naphtha, is a crystalline, aromatic, white, solid hydrocarbon with formula C
10H
8 and the structure of two fused benzene rings. It is best known as the traditional, primary ingredient of mothballs...
.
Carbon monoxideCarbon monoxide is a colorless, odorless and tasteless gas, yet very toxic to humans. It consists of one carbon atom and one oxygen atom, connected by a covalent double bond and a dative covalent bond...
and smoke
tarTar is modified resin produced primarily from the wood and roots of pine by destructive distillation under pyrolysis. It is a viscous black liquid. Production and trade in tar was a major contributor in the economies of Northern Europe and Colonial America. Its main use was in preserving and...
s were also reduced, but not quantified.
These positive results are in contrast to
MAPSMaps is the plural of map, a visual representation of an area.As an acronym, MAPS may refer to:* Mail Abuse Prevention System* Manx Aviation Preservation Society...
/NORML's previous studies into vaporizers which found less encouraging results, leading one to the conclusion that the effectiveness of vaporization varies greatly from vaporizer to vaporizer. See Factors affecting vaporizer output for possible causes of variation.
A 1996 MAPS study tested two simple vaporizer models against water pipes and filtered and unfiltered cannabis cigarettes (
jointJoint is slang for a cigarette rolled using cannabis. Rolling papers are the most common rolling medium among industrialized countries, however brown paper, cigarettes with the tobacco removed, and newspaper are commonly used throughout the developing world. Modern papers are now commonly made...
s). The smoke produced by each was analyzed for solid particulates (tars) and 3 major cannabinoids. The various smoking methods were then rated based on their cannabinoid-to-tar ratio. The two tested vaporizers performed up to 25% better than unfiltered cannabis cigarettes (second best) in terms of tar delivery. However, both vaporizers produced more than ten times more tars than cannabinoids, which may partly be attributable to the low potency (2.3%) of the
NIDANida or NIDA may refer to:*National Institute of Development Administration, a graduate university in Bangkok, Thailand*Nida in Poland*Nida, Final Fantasy VIII*Nida, Świętokrzyskie Voivodeship *Nida, Lithuania, a town...
-supplied cannabis used in the study. Surprisingly, the same study found that water pipes (bongs) and filtered cigarettes performed 30%
worse than regular, unfiltered joints. The reason was that waterpipes and filters filter out psychoactive THC with the tars, thereby requiring users to smoke more to reach their desired effect. The study did not, however, rule out the possibility that waterpipes could have other benefits, such as filtering out harmful gases such as carbon monoxide.
These studies have not measured the presence of toxic gases, such as
ammoniaAmmonia is a compound of nitrogen and hydrogen with the formula NH
3. It is normally encountered as a gas with a characteristic pungent odor. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to foodstuffs and fertilizers...
,
hydrogen cyanideHydrogen cyanide is a chemical compound with chemical formula HCN. A solution of hydrogen cyanide in water is called hydrocyanic acid. Hydrogen cyanide is a colorless, extremely poisonous, and highly volatile liquid that boils slightly above room temperature at 26 °C...
and carbon monoxide, though previous studies have indicated unquantified decreases in carbon monoxide with vaporization.
Although vaporizers produce cleaner vapors than smoking, they do not completely eliminate respiratory irritation. A large puff of potent vaporized cannabis will often cause severe coughing. This is likely due to the THC itself, which is known to have a strong expectorant effect.
Efficacy
The wide range of results from tests of different vaporizers suggest that the choice of vaporizer is a major factor in determining extraction and delivery efficacy as well as the amount of harmful byproducts produced. In Cannabis and many other medicinal plants, the components responsible for the aromatic nature of the plant will often vaporize at a low-end temperature in the range of extraction temperature values for all the bioactive components. In Cannabis, the temperature range across which the actives will vaporize is at least starting at around where only aromatic compounds of minimal bioactivity will release and going all the way up to with the higher end of this range representing where the cannabinoids of higher bioactivity appear to be released. It is believed that both the total amount of actives delivered as well as the breadth of spectrum delivered per inhalation is critical in determining the value of the delivered dose and, in turn, systems that deliver the highest amount of actives and broadest spectrum of actives per inhalation are believed to be the most effective for medicinal applications: i.e. venturi enhanced extraction / convection based systems.
Proposed factors affecting output include:
- Temperature
- Specimen density
The density of a material is defined as its mass per unit volume. The symbol of density is ρ .- Formula :Mathematically:where: is the density, is the mass, is the volume....
- Weight, content of water and essential oil
An essential oil is a concentrated, hydrophobic liquid containing volatile aroma compounds from plants. Essential oils are also known as volatile or ethereal oils, or simply as the "oil of" the plant from which they were extracted, such as oil of clove. An oil is "essential" in the sense that it...
s
- Consistency of material in the filling chamber
- Variety and potency of cannabis used
- Different preparations such as crude flower tops, hashish
Hashish is a preparation of cannabis composed of the compressed stalked resin glands called trichomes, collected from the cannabis plant. It contains the same active ingredients but in higher concentrations than other parts of the plant such as the buds or the leaves...
, hash oilHash oil is a solution of tetrahydrocannabinol, but is a misnomer in suggesting any resemblance to hashish. It is made out of cannabis and is very potent due to its high THC concentration, which generally varies between 15 and 20%, but can reach 60 to 70% in some cases.Also known as lube, oil or...
, etc.
- Storage time of the vapor
- Proportion of THC exhaled (breathing technique)
Not all those have been scientifically tested. Research using the vaporizer found the delivery efficiency highest at around , falling to about half efficiency at to degrees depending on material.
The purest preparations produced the highest efficiencies, about 54% for pure THC versus 29% for plant material (female flower tops) with 12% THCA content. Besides THC, several other cannabinoids as well as a range of other plant components including terpenoids were detected in the plant material. Using pure THC in the vaporizer, no degradation products (delta-8-THC (D8-THC), cannabinol (CBN), or unknown compounds were detected by HPLC analysis. The longer vapor is stored, the more of the THC is lost as it condenses on the surface of the vaporizer or the balloon. This loss may be negligible over a few minutes but may exceed 50% after 90 minutes. The Leiden University study found that as much as 30%–40% of inhaled THC was not absorbed by the lungs and simply exhaled. However, they did not find large individual differences in the amounts exhaled.
Use in the restaurant industry
A bit of vapor is sometimes used by chefs as a method of applying controlled heat to herbs and spices to release flavors that are otherwise difficult to titrate or apply, or that might be spoiled by overheating during cooking. "Chicago's Achatz uses the aroma-filled bags as place-mats, punctured when plates are placed in front of the customer."
Table of vaporization temperatures
| Plant common name |
Scientific name |
Part utilized |
Temperature |
| Aloe Vera |
 Aloe VeraAloe vera, also known as the medicinal aloe, is a species of succulent plant that probably originated in Northern Africa. Aloe vera grows in arid climates and is widely distributed in Africa and other arid areas. The species is frequently cited as being used in herbal medicine. Many scientific...
|
Gelatinous fluid from leaves |
|
| Cannabis |
 Cannabis sativaCannabis sativa is an annual plant in the Cannabaceae family. It is a herb that has been used throughout recorded history by humans as a source of fiber, for its seed oil, as food , as a drug , as medicine , and for spiritual purposes...
|
Flowers |
|
| Eucalyptus |
 Eucalyptus globulusThe Tasmanian Blue Gum, Southern Blue Gum or Blue Gum, is an evergreen tree, one of the most widely cultivated trees native to Australia. They typically grow from 30 to 55 m tall. The tallest currently known specimen in Tasmania is 90.7 m tall. There are historical claims of even taller trees,...
|
Leaves |
|
| Hops |
Humulus lupulusHumulus lupulus is a species of Humulus in the Cannabaceae family.Common hop is a dioecious, perennial herbaceous climbing plant which sends up new shoots in early spring and dies back to the cold-hardy rhizome in autumn...
|
Cones |
|
| Chamomile |
 Chamomilla recutita |
Flowers |
|
| Clove |
 Syzygium aromaticum |
Dried flower buds |
|
| Gingko |
 Ginkgo Biloba |
Leaves, seeds |
|
| Lavender |
 Lavandula angustifoliaLavandula angustifolia Lavandula angustifolia Lavandula angustifolia (also Lavandula spica or Lavandula vera; common lavender, true lavender, or English lavender (though not native to England); formerly L...
|
Leaves |
|
| Lemon balm |
 Melissa officinalis |
Leaves |
|
| Sage |
 Salvia officinalis |
Leaves |
|
| Thyme |
 Thymus vulgarisThymus vulgaris or Common Thyme is a low growing herbaceous plant, sometimes becoming somewhat woody. It is native to southern Europe. It is much cultivated as a culinary herb.It typically grows as a sub-shrub, between 15 and 20cm tall.- Uses :...
|
Herb |
|
| Tobacco |
 Nicotiana tabacumNicotiana tabacum, or cultivated tobacco, is a perennial herbaceous plant. It is found only in cultivation, where it is the most commonly grown of all plants in the Nicotiana genus, and its leaves are commercially grown in many countries to be processed into tobacco. It grows to heights between 1...
|
Leaf |
|