LOW-TECH MAGAZINE

Too Much Combustion, Too Little Fire

The fire – which we have used in our homes for over 400,000 years – remains the most versatile and sustainable household technology that humanity has ever known. The fire alone provided what we now get through a combination of modern appliances such as the oven and cooking hob, heating system, lights, refrigerator, freezer, hot water boiler, tumble dryer, and television. Unlike these newer technologies, the fire had no need for a central infrastructure to make it work, and it could be built locally from readily available materials.

Vietnam's Low-tech Food System Takes Advantage of Decay

The food system in the industrialised world is based on mass-production, global distribution, and constant refrigeration. It requires many resources and produces a lot of food waste.

Aaron Vansintjan takes to the streets of Hanoi, where the Vietnamese practice a food culture based largely on fermentation.

Although food spoils much faster in a tropical climate, the Vietnamese will often store it without refrigeration, and instead take advantage of controlled decay. Vietnam's decentralised food system has low energy inputs and reduced food waste, giving us a glimpse of what an alternative food system might look like.

If We Insulate Our Houses, Why Not Our Cooking Pots?

While modern cooking stoves are convenient, when it comes to energy use they leave a lot to be desired. As we have seen in the previous article, the thermal efficiency of an electric hob does not exceed that of a conventional open fire. In both cases almost 90% of the primary energy is lost during the cooking process.

Cooking food could be achieved in a far more energy efficient way, especially if the cooking pot itself is insulated. This is the principle behind the fireless cooker, a well-insulated box that keeps food simmering with only the heat of the cooking pot itself. A fireless cooker doubles the efficiency of any type of cooking device because it shortens the time on the fire and limits heat transfer losses.

In the early twentieth century, fireless cookers were common additions to western kitchens, similar to the refrigerator or cooking stove. Some models even integrated fireless cookers with gas or electric hobs. These functioned by lowering an insulated hood over the cooking pot once the heat had been switched off.

Well-Tended Fires Outperform Modern Cooking Stoves

Despite technological advancements since the Industrial Revolution, cooking remains a spectacularly inefficient process. This holds true for poor and rich countries alike. While modern gas and electric cooking stoves might be more practical and produce less indoor pollution than the open fires and crude stoves used in developing countries, they are equally energy inefficient.

In fact, an electric cooking stove is only half as efficient as a well-tended open fire, while a gas hob is only half as effective as a biomass rocket stove. And even though indoor air pollution is less of an issue with modern cooking stoves, research indicates that pollution levels in western kitchens can be surprisingly high.