Kelly Kettle, Storm Kettle, Thermette and Volcano Kettle are trade names for efficient portable devices for boiling water outdoors using twigs and other small combustible materials; these devices consist of a water jacket surrounding a fire chamber which creates an upward chimney draft ensuring efficient and rapid boiling even in windy or wet weather.
Kelly Kettle and Volcano Kettle are registered trademarks of the Kelly Kettle company which first produced the product in Ireland in the early 1900s. The Thermette was first manufactured in New Zealand in 1929 and was standard issue for the New Zealand Army during World War II where it was known as a Benghazi boiler. Other companies, including the Eydon Kettle Company started manufacture at later dates.
Early examples (estimated at about 3,600 years) of devices that heat water surrounding a fire include samovar tea urns from Eastern, Central, and Southeastern Europe, as well as the Middle East. The Kelly Kettle Company first manufactured portable devices of this type four generations ago in the early 1900s. The Thermette was invented in 1929 in New Zealand by John Ashley Hart. It was standard issue to the New Zealand army serving in the North Africa during WW2 when it was known as the 'Benghasi Boiler'. In 1939 the New Zealand Army asked Hart to waive his patent so they could make their own Thermettes; he agreed and the device was issued as standard equipment to every small army unit.
A modified version of the idea was created by the Eydon Kettle Company in the early 1970s and sold as the 'Storm Kettle'. Fixed (and portable) rocket stoves used for cooking were developed in 1980s; with variants for heating water and for space heating.
The kettles are normally constructed from a durable heat-conductive metal, such as aluminium, stainless steel, copper or tin. The source of heat is typically from small items of combustible material such as paper and twigs. A base placed below the main body section holds the fuel and contains the fire whilst it burns. Additional fuel can be added to the fire without removing the kettle by dropping it down the chimney. Common among all designs is the principle of internal chimney to create the efficient upward draught of heat.
Variations on around a core design have been produced by a number of manufacturers. Typical water capacities are between 0.5–1.5 litres (2–6 cups worth). Some kettles have the flame holder at the base integral and some allow it to be removed. Typically, the designs use a vertical cylinder shape for the outside of the kettle with the internal surface of the chimney being either a straight cylinder or a cone shape with a wide end at the base and a smaller aperture at the top.
If the base is removable, it may be possible to store other items, or specially designed cook sets within the chimney during transport. Devices normally come with a swinging or fixed handle depending on the design. A cork, plastic stopper or in some cases a whistle are used to seal the water container spout, however the cork and stoppers should only be used when transporting water and NOT be used while the water is being heated. If left in place even loosely the hot water vapor can make the cork swell and hold fast, and then the pressure builds up until the cork pops out followed by a jet of hot/boiling water gushing out.
Cooking accessories are available for some units to allow a small cooking pot to be placed on a support on top of the chimney, or a grill to be put over the base without using the main water chimney component. These add-ons typically store inside the chimney for transport.
Further add-ons can turn the chimney into a small cooking range, with the cooking containers and utensils also being packed into the hollow chimney space or into the Inverted base. The fire bases may be inverted and stored inside the chimney.
The 'Eco-Bily' is composed of stainless steel with a 0.7–1.5-litre capacity with parallel external sides and top, with a fixed base that cannot be removed from the kettle; fuel is added exclusively by inserting it via the chimney.
The 'Dingo Bush Kettle', has a removable bottom plate for the fire base, which is integral to the kettle. It has a slightly different shape, being more rounded than the other kettles.
Britain and Ireland
The "Volcano Kettle" from the Kelly Kettle Company, the "Storm Kettle" by the Eydon Kettle Company and "Ghillie-Kettle" from Spinform have capacities of between 0.4–1.5 litres. The common design has a removable base, inside which the fire is lit.
The Thermette design originates as an independent invention in 1929 by John Ashley Hart. It uses an internally narrowing (conical) chimney and a construction of either copper or tin plate. The shape is a straight cylinder leading up to a flat top; the water spout also being on the flat top. Pouring is done with a fixed, handle on the side, and the base can be removed. The Thermette is considered a New Zealand cultural icon.
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- Akhundov, Tufan (Autumn 2000), "Birth of the Samovar?", Azerbaijan International (8.3), pp. 42–44
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- "Thermette's History". Thermette. Retrieved 2010-02-22.
- "The STORM Kettle". Eydon Kettle Company. Retrieved 2010-02-22.
- "Whole stoves". Aprovecho. Retrieved 2009-04-13.
- "Rocket Stove Water Heating System (Set)".
- "Rocket Mass Heaters".
- "Eco billy". Eco billy. Retrieved 2010-02-23.
- "The Dingo Bush Kettle". BushKettle. Retrieved 2010-02-23.
- "Eydon Kettle Company". Retrieved 2010-02-23.
- "Ghillie Kettle Company". Retrieved 2010-02-23.
- "THE "THERMETTE", NZ Truth, 11 December 1930
- "Thermette now!", 1938 pictorial advetisment, Evening Post
- "Using a Thermette", Te Ara
- Kelly Kettle Company
- Eydon Kettle Company
- Ghillie Kettle Company
- Ghillie Kettle North America
- Thermette (video) from Te Ara Encyclopaedia of New Zealand
- Campmaster Tin Thermette (New Zealand)
- Dingo Bush Kettle; Australian version
- Thermette North America
- Backcountry Boiler; a modern lightweight (225 gram) variant intended for camping
- A short article with a cross section of a thermette