Three types of liquefied petroleum gas burn in torches for various professional uses, home uses and hobbies. Your choice between MAPP gas, butane or propane depends on your application.
Liquefied Petroleum Gas
Manufactured from crude oil, liquefied petroleum gases, or LPGs, remain in a liquid state while stored in tanks. When released into the torch, they evaporate and the gas mixes with air and burns.
MAPP gas, made from combining liquefied petroleum and methylacetylene-propadine, burns the hottest, around 3650 degrees F, or 2010 degrees C. Best uses include hard or silver soldering and brazing. But take care: MAPP gas may burn too hot for some applications.
Propane, the most common of the three, does not burn as hot as MAPP gas, but is available at more retail outlets in more forms. In a torch, it can be used for soft soldering copper pipes. For safety, you should store propane outdoors.
The least toxic of the three, butane burns the cleanest, and you can safely store it indoors. It burns at about the same temperature as propane and serves much the same uses, but may cost more. Butane will not evaporate at lower temperatures so torches won't work at very cold temperatures.