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 to180°C, 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 and reduced noxious gases such as carbon monoxide. The vaporizing chamber accommodates a porous liquid delivery device which communicates with an external liquid source via liquid supplier.

Liquid to be vaporized is exposed to the by-passing gas through the medium of the liquid delivery device. According to the invention, the liquid is exposed to the gas exclusively via the pores in the liquid delivery device and the liquid supplier are controllable. With little to no smoke produced, cooler temperatures, and less material required to achieve the same effect, the irritating effects of smoking are greatly reduced or eliminated along with second hand smoke by using a grinder. This makes vaporizers useful in places where there are public bans on smoking. Vapors may be filtered and cooled further using a water pipe or an inline water attachment.