Vaporizer (cannabis)
A vaporizer or vapouriser is a device used to extract the active ingredients of plant material so that they can be breathed. It is often used for cannabis, tobacco, or other herbs such as chamomile.
Vaporization vs. smoking
Vaporization is an alternative to smoking. It doesn't make smoke or other cancer-causing by-products. It does that by heating the material so that the active compounds boil into a vapor. Nothing actually burns, so there is no smoke or taste of smoke. Vapor ideally contains almost no particulate matter or tar, and much less noxious gas such as carbon monoxide. The vapor can be collected in a jar or inflatable bag, or inhaled directly.
Cooking
Vaporizers are sometimes used by chefs. They use them to heat herbs and spices to release flavors that are otherwise difficult to extract, 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.