A beverage-can stove, or pop-can stove, is a do it yourself, ultralight, alcohol-burning portable stove. It is made using parts from two aluminium beverage cans. Basic designs can be relatively simple, but many variations exist. Total weight, including a windscreen/stand, can be less than one ounce (28 g). The design is popular in ultralight backpacking due to its low cost and lighter weight than commercial stoves. This advantage may be lost on long hiking trips, where a lot of fuel is packed, since alcohol has less energy per gram than some other stove fuels. Of the available fuels, methanol delivers the least energy, isopropyl alcohol delivers more, butanol is hardly ever used, and pure ethanol the most. Denatured alcohol and rubbing alcohol are frequently used for this purpose, as it often contains a mixture of ethanol and other alcohols. All but isopropyl alcohol burn with a smokeless flame; it can provide both light and heat. History and design The basic design dates back more than a century. It consists of a double-wall gas generator, a perforated burner ring, and an inner preheat chamber. A similar design was patented in 1904 by New York coppersmith J. Heinrichs. Trangia has been selling a commercial version of the design since 1925, and Safesport marketed a stainless-steel stove in the 1990s. The Trangia stove burner is made from brass, although all the other associated parts that come with it are aluminium. In the unpressurized open-top design the double wall acts as a gas generator, transferring heat from the flame to the fuel. This effect enhances combustion, producing more heat than other passive designs. The inner wall also creates a convenient preheat chamber for starting the stove. Once the fuel has warmed up, its vapor will travel up the hollow wall, pass through the perforations, and form a ring of flame. This improves air/fuel mixing and therefore combustion. Vapor also rises from the center of the stove and burns when passing through the ring of flame as long as a pot is over the stove. Pressurized designs have no cut-out in the top. They are filled with alcohol by separating the two halves of the burner, by opening a plug to a smaller hole in the center of the top side or by filling through the gas-jet holes. A wick may be inserted into the hollow wall, where it will draw fuel upwards closer to