Vaporizers

A vaporizer is a device used to release the active ingredients of plant material, commonly cannabis or tobacco, or to release therapeutic compounds from herbs. Vaporizing is an alternative to smoking. Rather than burning the herb, which produces numerous harmful by-products, a vaporizer heats the material, ideally to 180°C (356°F), so that the active compounds contained in the plant melt, causing a phase change of the matter, which is now an aromatic vapor. This new gas is not smoke from combustion, but an evaporated vapor that has the appearance of smoke. This vapor ideally contains virtually zero particulate matter (tar) and reduced noxious gases such as carbon monoxide. Vapors may be filtered and cooled further using a water pipe or an inline water/ice attachment. The vapors are then inhaled directly - through a hose or pipe, or are then stored for subsequent inhalations in container such as a "dome" or "balloon". With little to no smoke produced, cooler temperatures, and less material required to achieve the same effect, the irritating/harmful effects of smoking are greatly reduced or eliminated along with second-hand smoke by using a vaporizer. This makes vaporizers useful in places where there are public bans on smoking.

The shortcomings of smoked cannabis have been widely viewed as a major obstacle for the approval of medical marijuana. In response, several scientific studies have tried to establish whether vaporizers could offer a clinically reliable and safe method of cannabis use. Though vaporizers show great variations of performance, model to model, such studies have always found vaporization superior to smoking. When using high-end vaporizers along with high grade cannabis (containing elevated levels of THC), all undesired compounds are found to be eliminated, in a manner consistent enough for clinical trials. In comparison to other THC delivery methods such as ingestion, vaporization offers the advantages of: rapid onset, direct delivery into the bloodstream, and the possibility to gradually increase delivery until the desired level is reached; enabling for more effective self-dosage.

Vaporizers are available in many varieties and price ranges.
Simple vaporizers commonly use a lighter as heat source.
Precise vaporizers use an electric heating element, often featuring a temperature control.
High-end models may cost from one to several hundred dollars.

Broadly, vaporizers may be classified by how they heat the substance:

In conduction heating, the substance is placed on a metal plate that is then heated to release the active constituents. The direct contact between hot metal and the herbs can cause them to burn; thus this is not a preferred approach and is rarely used in modern vaporizer designs.

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, especially if the extraction chamber utilizes Venturi-effect design.

In radiation heating, the substance is subjected to bright light. The substance absorbs radiant energy and its temperature raises.

Many convection vaporizers use a tube, called a whip, that is held to the heat source, 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.

Another important classification for vaporizers includes the type of materials used in the heating element, the extraction chambers, and delivery means. Most common wood box and whip type vaporizers use a heating element with a glass extraction chamber and plastic or rubber tubing for delivery. This is a very effective approach. However, there are concerns about off-gassing depending on what materials were used in the construction. Certain vaporizers utilize a heating chamber completely separated from all electronics. Some companies, are now using a higher-grade plastic hose while the makers of the higher end vaporizers have opted for a silicone hose. A high end vaporizer made in Germany, uses an aluminum heat exchanger and a food grade plastic bag, known as a zeppelin, for storage and delivery.

Regardless of the benefits of medical cannabis, the widely perceived health risks of smoking as a route of administration have been viewed as a major obstacle for the legal approval of cannabis for medical uses, though some studies indicate that the expectorant activity of THC may help the lungs remove much of the inhaled tar through coughing. In response to the concerns, several studies have aimed to establish whether or not vaporizers could offer a clinically reliable and safe route of administration for cannabis. Though vaporizers show great variations in performance, such studies have consistently found vaporization superior to smoking and with best case (high-end vaporizers used with potent cannabis) results showing an elimination of undesired compounds suitable for clinical trials. In comparison to other routes of administering cannabis such as eating, vaporization offers the advantages of inhalation - immediate delivery into the bloodstream, rapid onset of effect, and more precise titration, the ability to more accurately control the dosage to produce a desired effect.

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 efficiency as well as the amount of harmful byproducts produced, or not produced, as in the case of a superior system. 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 56°C (132°F) starting at around 127°C (260°F) where only aromatic compounds of minimal bioactivity will release and going all the way up to 200°C (392°F) 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.

Unlike the black ashes produced by burning plants, the byproducts of vaporization are usually brown. The vaporized remains of cannabis may still contain THC or any number of the other 60 cannabinoids found in the plant that may not be vaporizable. It is possible to extract these cannabinoids using a number of methods, including cooking, making a tincture, or re-vaporizing. It is also possible to smoke these remains and gain a mild psychoactive effect, but the negative health effects typically leave this option as a last resort for someone seeking a high.

Conduction vaporizer from the 1970's	Verdamper vaporizer	Volcano digital vaporizer

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