Methylated spirits ("metho") is a mixture of ethyl alcohol (95%) and methyl alcohol (%5).
The methyl alcohol is poisonous and is added to prevent the methylated spirits being
used as cheap drinking alcohol.
Ethyl alcohol, or ethanol, is produced by the fermentation of sugars, or from direct
synthesis from ethylene. It is a renewable energy source.
Ethanol's formula is C2H5OH. Its boiling point is 78.5 deg C, and its melting point is -117.3 deg C.
Ethanol burns with a hot, pale-blue flame. It is miscible with water. Uses include
consumption in alcoholic beverages, a solvent, an anti-freeze solution, and a fuel. Ethanol is used as an additive to car fuel and
is burnt with liquid oxygen in some rocket engines. When Ethanol is burnt in air, the results of combustion are carbon dioxide and water.
Methyl alcohol, or methanol, is also sometimes called wood spirit. It is produced by
the destructive distillation of wood, or by a synthetic process which involves reacting carbon
monoxide with hydrogen gas.
Methanol's formula is CH3OH. Its boiling point is 64.6 deg C, and its melting point is -97 deg C.
Methanol burns with a pale, non-luminous flame. It is poisonous and, if consumed, causes blindness, insanity, and eventual death.
It is commonly used as a denaturant for ethyl alcohol, and is miscible with water.
Methylated spirits as a fuel
The energy released from burning ethanol is approximately 30 kJ/g. For comparison, the energy released during the
combustion of propane and butane are about 50 kJ/g and 49 kJ/g respectively.
It is simple to use metho as a cooking fuel - simply place about 30 ml in a small metal
container and light it. If you support a cooking pot over the flame, you can
boil a litre of water in about 16 minutes - no special equipment required! I tried
a stainless steel egg cup and it worked fine.
More efficient metho burners have a series of small holes which act as jets that the metho
burns from. Such burners can boil a litre of water in about 8 or 9 minutes.
Its also usful to know that mixing metho with 10% water can reduce the soot produced when its burnt.
Safety precautions with metho
Although relatively safe compared to other stove fuels, metho is a flamable and toxic
substance which needs to be handled carefully. Here are a couple of safety hints:
- Do not refill a metho burner until it is cool enough to touch. This is to avoid accidentally igniting the fuel bottle.
- Do not store metho in a container which you later intend to use to hold drinking water - you will not be able to get rid of the foul taste! It is best to
store it in a properly labelled fuel container such as a Nalgene fuel bottle.
- If you get metho on your hands, rinse them thoroughly before handling food.
Names for methylated spirits around the world
In the UK, Australia, and New Zealand, metho is called methylated spirits.
In the US and Canada its called denatured alcohol, methyl hydrate*, or fondue fuel. In Europe, it may be called spirits,
brennspirits (Germany), alcool a bruler (France), or alcool etilico denaturato (Italy).
It is generally available in hardware stores, supermarkets, service stations, and camping/outdoors stores. Methylated spirits may not be available in some countries due to alcohol restrictions (e.g. Pakistan).
Other uses for Metho
Metho is also a handy solvent for cleaning applications such as removing water based paint.
* Methyl hydrate is pure Methanol.
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