Pure forms of alcohol, such as denatured alcohol, may be used indoors with adequate ventilation. However, some forms may be toxic and need more ventilation due to toxins produced from combustion. The following forms of alcohol are good candidates for use as a fuel source.
Isopropyl alcohol (rubbing alcohol) is an acceptable cooking fuel. It may be purchased in 70 percent, 91 percent, and 99 percent strengths. The higher the percentage of alcohol, the better the alcohol will burn. Isopropyl alcohol produces a yellow flame and does not burn as cleanly denatured alcohol or ethanol.
Denatured alcohol is often recommended by manufacturers of alcohol stoves. It can be purchased online or in hardware stores in the paint section.
Ethanol or ethyl is about 95 percent alcohol and is a fantastic fuel for burning indoors. It burns so cleanly that the flame is blue or nearly invisible.
Remember that any flame can produce carbon monoxide. Although alcohol is one of the safest fuels to burn indoors, proper ventilation is required to ensure adequate oxygen is available for complete combustion to prevent carbon monoxide from building up. Be sure to keep a working carbon monoxide detector with a digital readout nearby when burning anything!
Alcohol is a great storage fuel and has an indefinite shelf life if stored in a tightly sealed container. Alcohol will evaporate quickly if left open and lose potency. Alcohol has a low flash point, which means that it catches on fire very quickly. Alcohol burns about half as hot as some other fuels but is a great choice for cooking indoors. It is extremely flammable, but not explosive.