Any form of cooking will destroy some nutrients in food, but the key variables are how much water is used in the cooking, how long the food is cooked, and at what temperature.[44] Nutrients are primarily lost by leaching into cooking water, which tends to make microwave cooking healthier, given the shorter cooking times it requires.[45] Like other heating methods, microwaving converts vitamin B12 from an active to inactive form; the amount of conversion depends on the temperature reached, as well as the cooking time. Boiled food reaches a maximum of 100 °C (212 °F) (the boiling point of water), whereas microwaved food can get locally hotter than this, leading to faster breakdown of vitamin B12. The higher rate of loss is partially offset by the shorter cooking times required.[46]

However, unlike the smaller model, this Toshiba has a learning curve to navigating the other controls. When you hit the sensor reheat button on the control panel, you’re given the option of choosing between several cryptic codes. By consulting the legend on the inside of the microwave, you’ll discover that these codes correspond to various commands: reheat, frozen pizza, frozen entree. Oddly, several of these commands already have their own buttons on the control panel, which means there are two ways to perform the same action. The Soften/Melt button also has a jumble of codes you have to scroll through, and you’ll need to refer to the legend if you want to decipher what they mean. While we didn’t find these commands intuitive, we don’t think they’re a dealbreaker since most people won’t use them that much anyway.


When shopping for the right model, consider the size, price, and type (countertop or over-the-range), depending on your kitchen space. Over-the-range microwaves are usually mounted over your stovetop, and they have a light and ventilation underneath. Depending on the model, you can also have the countertop or over-the-range microwave built into your kitchen setup. The options are limitless, fam.
Due to this phenomenon, microwave ovens set at too-high power levels may even start to cook the edges of frozen food while the inside of the food remains frozen. Another case of uneven heating can be observed in baked goods containing berries. In these items, the berries absorb more energy than the drier surrounding bread and cannot dissipate the heat due to the low thermal conductivity of the bread. Often this results in overheating the berries relative to the rest of the food. "Defrost" oven settings either use low power levels or turn the power off and on repeatedly - designed to allow time for heat to be conducted within frozen foods from areas that absorb heat more readily to those which heat more slowly. In turntable-equipped ovens, more even heating will take place[citation needed] by placing food off-centre on the turntable tray instead of exactly in the centre, so that no part of the food item will be continuously unheated by the center "dead zone".
Closed containers, such as eggs, can explode when heated in a microwave oven due to the increased pressure from steam. Intact fresh egg yolks outside the shell will also explode, as a result of superheating. Insulating plastic foams of all types generally contain closed air pockets, and are generally not recommended for use in a microwave, as the air pockets explode and the foam (which can be toxic if consumed) may melt. Not all plastics are microwave-safe, and some plastics absorb microwaves to the point that they may become dangerously hot.
A variant of the conventional microwave is the convection microwave. A convection microwave oven is a combination of a standard microwave and a convection oven. It allows food to be cooked quickly, yet come out browned or crisped, as from a convection oven. Convection microwaves are more expensive than conventional microwave ovens. Some convection microwaves—those with exposed heating elements—can produce smoke and burning odors as food spatter from earlier microwave-only use is burned off the heating elements.

Uneven heating in microwaved food can be partly due to the uneven distribution of microwave energy inside the oven, and partly due to the different rates of energy absorption in different parts of the food. The first problem is reduced by a stirrer, a type of fan that reflects microwave energy to different parts of the oven as it rotates, or by a turntable or carousel that turns the food; turntables, however, may still leave spots, such as the center of the oven, which receive uneven energy distribution. The location of dead spots and hot spots in a microwave can be mapped out by placing a damp piece of thermal paper in the oven. When the water saturated paper is subjected to the microwave radiation it becomes hot enough to cause the dye to be released which will provide a visual representation of the microwaves. If multiple layers of paper are constructed in the oven with a sufficient distance between them a three-dimensional map can be created. Many store receipts are printed on thermal paper which allows this to be easily done at home.[40]
Microwave heating can be deliberately uneven by design. Some microwavable packages (notably pies) may include materials that contain ceramic or aluminium flakes, which are designed to absorb microwaves and heat up, which aids in baking or crust preparation by depositing more energy shallowly in these areas. Such ceramic patches affixed to cardboard are positioned next to the food, and are typically smokey blue or gray in colour, usually making them easily identifiable; the cardboard sleeves included with Hot Pockets, which have a silver surface on the inside, are a good example of such packaging. Microwavable cardboard packaging may also contain overhead ceramic patches which function in the same way. The technical term for such a microwave-absorbing patch is a susceptor.[43]
Sir Henry Tizard travelled to the U.S. in late September 1940 to offer the magnetron in exchange for their financial and industrial help (see Tizard Mission).[7] An early 6 kW version, built in England by the General Electric Company Research Laboratories, Wembley, London, was given to the U.S. government in September 1940. The magnetron was later described by American historian James Phinney Baxter III as "[t]he most valuable cargo ever brought to our shores".[9] Contracts were awarded to Raytheon and other companies for mass production of the magnetron.

Every microwave oven contains a magnetron, which generates microwaves. Those waves are then guided into the oven’s cavity, where they bounce around, rapidly swinging the polarity of charged molecules in foods (particularly water, fats, and sugars) and generating heat. Metal mesh on the door keeps those large-wavelength microwaves from escaping the metal box and cooking you. (This great video uses a disassembled model to explain further.)


In our heat map test, the Toshiba produced the most even heating pattern of all the microwaves we tested, perfectly browning the layer of marshmallows from edge to edge. It expertly cooked a baked potato in about 6 minutes, which was average for the microwaves we tried. It also reheated beverages well and perfectly cooked frozen macaroni and cheese. And it made tasty popcorn, with only 5 grams of kernels left unpopped, which was on a par with most of the models we tested. This model allows you to defrost by time or weight, but like most of the microwaves we tested, it didn’t defrost meat well.
For an over the range microwave, you need the right kind of airflow for your setup, and you may need additional features like the ability to control oven range lights. Over the range units are specifically designed for these tasks, but they vary from model to model, so don’t get complacent when buying. Know what you need to keep your stove clear of smoke first!

Any form of cooking will destroy some nutrients in food, but the key variables are how much water is used in the cooking, how long the food is cooked, and at what temperature.[44] Nutrients are primarily lost by leaching into cooking water, which tends to make microwave cooking healthier, given the shorter cooking times it requires.[45] Like other heating methods, microwaving converts vitamin B12 from an active to inactive form; the amount of conversion depends on the temperature reached, as well as the cooking time. Boiled food reaches a maximum of 100 °C (212 °F) (the boiling point of water), whereas microwaved food can get locally hotter than this, leading to faster breakdown of vitamin B12. The higher rate of loss is partially offset by the shorter cooking times required.[46]
This GE microwave oven with a 16-inch turntable proves you don't need to spend a bundle to get perfectly "baked" potatoes, steamed broccoli, or evenly heated mac 'n cheese. Thanks to a smooth control panel with lettering that contrasts well with the background, it's super easy to read the display and wipe it clean. If stainless steel isn't your style, this model also comes in black and white. 
A variant of the conventional microwave is the convection microwave. A convection microwave oven is a combination of a standard microwave and a convection oven. It allows food to be cooked quickly, yet come out browned or crisped, as from a convection oven. Convection microwaves are more expensive than conventional microwave ovens. Some convection microwaves—those with exposed heating elements—can produce smoke and burning odors as food spatter from earlier microwave-only use is burned off the heating elements.
Microwave ovens are frequently used for reheating leftover food, and bacterial contamination may not be repressed if the safe temperature is not reached, resulting in foodborne illness, as with all inadequate reheating methods. While microwaves can destroy bacteria as well as conventional ovens, they do not cook as evenly, leading to an increased risk that parts of the food will not reach recommended temperatures.[72]

With a capacity of 2.2 cubic feet, the stainless steel GE Profile microwave boasts a smooth easy-to-clean control panel and a large interior, making it a great model for big families. Seriously, you can heat an entire casserole or pizza on the 16-inch turntable and still have plenty of room to spare. It cooks evenly so you won't find a cold spot in the middle of your ziti and delivers perfectly steamed veggies.


In 1945, the heating effect of a high-power microwave beam was accidentally discovered by Percy Spencer, an American self-taught engineer from Howland, Maine. Employed by Raytheon at the time, he noticed that microwaves from an active radar set he was working on started to melt a chocolate bar he had in his pocket. The first food deliberately cooked with Spencer's microwave was popcorn, and the second was an egg, which exploded in the face of one of the experimenters.[10][11] To verify his finding, Spencer created a high density electromagnetic field by feeding microwave power from a magnetron into a metal box from which it had no way to escape. When food was placed in the box with the microwave energy, the temperature of the food rose rapidly. On 8 October 1945, Raytheon filed a United States patent application for Spencer's microwave cooking process, and an oven that heated food using microwave energy from a magnetron was soon placed in a Boston restaurant for testing.[12]
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