On a weekend hiking excursion I was introduced to a portable device used to boil water outdoors that was easy to use, efficient, lightweight and a perfect add to any outdoor adventure tool kit. Known widely by the trademarked name Kelly Kettle the device consists 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.
The leader of the hike had gathered various materials to demonstrate making tea in the wild. I watched in wonder as she filled the pot with water by the side opening, and proceeded to feed sticks into the top opening of the kettle. I was wondering what version of tea this would be as she didn’t take any care to remove dirt from the twigs we had gathered. As she lit the tinder in the base, I realized the kettle must be hollow as the flame shot out the top opening. She explained the general concept of the kettle and I was so intrigued of had to find out more so I did a bit of research and what I learned follows.
Early versions of water heaters surrounding a fire include bulkier tea urns used in Europe (dating back 3600 years.) The most common name in current times used for similar devices came to be with the popularity the version manufactured by the Kelly Kettle Company, which first manufactured portable devices of this type 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 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. Not to be left out, Australia has its own versions called The ‘Eco-Bily’ and The ‘Dingo Bush Kettle’.
The kettles are normally constructed from a durable heat-conductive metal, such as aluminium or stainless steel. Heat is generated from burning small items such as paper and twigs which 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.
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.