Solar Cookers
How we tested
Before we started to test solar cookers, we were skeptical—could anything simply left in a pot or box to cook in the sun actually taste good? But we were proved wrong—at least partially. We also didn't anticipate just how much fun solar cookers would be. Whenever we had a sunny day, we wanted to try cooking something new. But these results still beg the question: Are solar cookers more than just a toy for a food hobbyist?
Background
Cooking in the sun has a long history. The contemporary impetus for using solar cookers is largely economic and environmental. Solar cookers don't require any fuel, they don't create smoke pollution, and they use minimal water; all factors that make them attractive for use in developing regions around the world. Over 100,000 are reportedly used in India and China. Most solar cookers are produced by nonprofit organizations; profits from cookers sold in the U.S. or Europe subsidize cookers shipped elsewhere. In the U.S., sales are geared to several audiences: those who advocate environmentally sound practices, people in sunny climates who want a fuel-efficient way to cook that doesn't heat up the kitchen, outdoor enthusiasts who like their portability, and food hobbyists who enjoy experimental cooking.
There are two main types of solar cookers: concentrating or parabolic cookers and hot boxes or ovens. We tested one of each, as well as a hybrid form. The Hot Pot Solar Cooker ($100) is a large, insulated pot that sits on and is surrounded by reflector shields (metallic panels that concentrate the sun's rays at the pot). Its temperature stayed below 200 degrees. Our hot box model, the SOS Sport Solar Oven ($140), is a box with a specially molded insulating lid and insulated sides—its internal temperature reached 250 degrees in our tests. The Sun Oven ($200) is a combination of both types: The box has insulated sides and a glass top, and it’s ringed by reflectors. It reached an internal temperature of 350 degrees.
To cook effectively, it is necessary to understand some of the science that makes solar cookers work. It’s not the sun's heat that cooks the food, but rather the sun's ultraviolet rays. The sun must be high in the sky in order for the ultraviolet radiation to penetrate the atmosphere. For example, from November through March in the Northern Hemisphere, when the sun is low on the horizon, its light passes through more atmosphere to reach the earth. This screens out most of the UV rays—that's why it’s difficult to get a tan in the winter. When the sun is overhead, light rays pass through less atmosphere, so less UV radiation is screened out. A solar cooker works like a one-way lobster trap. It lets UV light rays in and then converts them to longer infrared light rays that can't escape. Infrared radiation has the right energy to make the water, fat, and protein molecules in food vibrate vigorously and heat up.
Practically, this means that successful cooking requires a clear sky, with the sun at least 45 degrees or more above the horizon for a significant amount of time (depending on what you're cooking, from two to eight hours). There are two easy ways to test for suitable conditions: 1) if your shadow is shorter than your height or 2) if the UV Index in your area is 7 or higher.
To determine local UV Index:
The EPA has a site that will calculate the local UV Index for that day based on zip codes:
The Results
Design Trifecta 360 Knife Block
Admittedly expensive, this handsome block certainly seemed to live up to its billing as “the last knife block you ever have to buy.” The heaviest model in our testing, this block was ultrastable, and its durable bamboo exterior was a breeze to clean. Well-placed medium-strength magnets made it easy to attach all our knives, and a rotating base gave us quick access to them. One tiny quibble: The blade of our 12-inch slicing knife stuck out a little.
Schmidt Brothers Downtown Block
This roomy block completely sheathed our entire winning knife set using just one of its two sides—and quite securely, thanks to long, medium-strength magnet bars. Heavy, with a grippy base, this block was very stable. An acrylic guard made this model extra-safe but also made it a little trickier to insert knives and to clean; the wood block itself showed some minor cosmetic scratching during use.
Schmidt Brothers Midtown Block
This smaller version of the Downtown Block secured all our knives nicely, though the blade of the slicing knife stuck out a bit. With a base lined with grippy material, this block was very stable. An acrylic guard afforded extra protection against contact with blades but made it a little harder to insert knives and to clean; the wood itself got a little scratched during use.
Swissmar Bamboo Magnetic Knife Block
This small, scratch-resistant model had a stable, rubber-lined base and could hold all our knives, though the blade of the 12-inch slicing knife stuck out a bit. But inch-long gaps between its small magnets made coverage uneven and forced us to find the magnetic hot spots in order to secure the knives. Its acrylic guard made it safer to use but harder to insert knives and to clean.
Messermeister Walnut Magnet Block
This handsome block was done in by its shape—a tippy, top-heavy quarter-circle that wasn’t tall or broad enough to keep the blades of three knives from poking out. It lacked a nonslip base, and its extra-strong magnets made it unnerving to attach or remove our heavy cleaver. Finally, it got a bit scratched after extensive use.
Epicurean Standing Knife Rack 12"
This magnetic block sheathed all our knives completely, though with a bit of crowding. But it was hard to insert each knife without hitting the block’s decorative slats on way down, and because the block was light and narrow, it wobbled when bumped. Worse, we couldn’t take it apart, so splatters that hit the interior were there to stay. Additionally, the outside stained easily, and when we wiped it down, the unit smelled like wet dog.
Kapoosh Rondelle Knife Block
This model stabilized knives with a mass of stiff, spaghetti-like bristles that shed and nicked easily after extensive use, covering our knives with plastic debris. While all our knives fit securely, several of the blades stuck out, making this unit feel less safe overall. Finally, though the bristles could be removed and cleaned in the dishwasher, their nooks and crannies made this block hard to wash by hand.
Kuhn Rikon Vision Knife Block, Clear
This plastic block required us to aim each knife into the folds of an accordion-pleated insert that was removable for easy cleaning but got nicked easily with repeated use. Because we could only insert the knives vertically, longer knife blades stuck out; a cleaver was too wide to fit. The lightest model in our lineup, this block was dangerously top-heavy when loaded with knives.