A solar cooker uses reflective panels or an insulated glazed box to trap sunlight around a black pot: a panel cooker reaches 100-120°C and a box cooker 150-180°C, enough to cook rice, beans and stews and to bake bread, with no fuel at all. Expect about twice the cooking time of a stove, start the meal two to three hours early, and use the same sunlight to make water safe by holding it at 65°C for 30 minutes.
Part of Solar Thermal Collectors
Solar cooking and pasteurization use sunlight to heat food and water directly, with no stove, no fuel and no moving parts.
Slow, Free Heat
A solar cooker collects the same sunlight as a collector but aims it at food, so it delivers a small, steady power rather than a flame. That sets the way you use it: put the food in early, leave it, and do not expect to stir-fry or boil a pot in minutes. The parent page puts cooking at roughly twice the time of a conventional stove, so start 2-3 hours before you want to eat. Minutes spent turning the cooker toward the sun every half hour or so keep it at full power.
The parent page puts a panel cooker at 100-120°C and a box cooker at 150-180°C; water is made safe by holding it at 65°C for 30 minutes. Three tools cover the field:
- Panel cooker — cardboard and foil panels that reflect sun onto a pot in a bag (Panel Cooker).
- Box cooker — an insulated glazed box with a reflector lid (Box Cooker).
- Water pasteurizer — any collector or cooker holding water at pasteurizing temperature, plus an indicator to prove it (Water Pasteurization (SODIS & WAPI)).
When Solar Cooking Fits
It suits clear weather and a cook who is home. It suits foods that tolerate long, moderate heat: rice, beans, stews, bread. It does not suit a shaded yard, a rushed meal, or a place with no spare hours in the day. As a second cooker alongside a rocket stove (Rocket Stove Design) it saves fuel on the days when sun is strong.
What You Need
- Cardboard or boards, foil or mirror for reflectors
- A black pot with a lid, thin metal, dark and matte
- A heat-resistant bag or an inverted glass bowl around the pot
- A thermometer, if you can find one
- Dark glasses for the cook, because reflected glare is intense
Common Mistakes
- Starting too late. The sun is strong for only a few hours around noon.
- Shiny pot. A bright pot reflects the heat away; use a black one.
- Leaving food warm for hours. Food cooked in the box that then sits warm (between about 4°C and 60°C) breeds bacteria; bring it above 60°C and eat it or cool it (Minimum Safe Temperatures).
Safety
Reflected glare, hot pots and unattended reflectors
Panels reflect the sun’s full brightness; wear dark glasses while tending the cooker and never aim a reflector at a person or at dry grass. Pots, lids and the box interior are hot enough to burn. Water that is only pasteurized, not boiled, has not been tested for chemical contamination: if you cannot confirm the temperature, boil it (Boiling Purification).
What’s Next
- Learn next: Box Cooker — the stable, hotter design
- Combine with: Solar Disinfection — the bottle method for water that needs no cooker