There’s a microwave in every kitchen. But despite the popularity of these brilliant appliances, many people still struggle with how to cook food evenly in a microwave. So, we have gathered the fundamentals of microwave cooking into three short lessons. Call it Microwaving 101!
Lesson One: How Does a Microwave Work?
Microwave ovens generate a form of high-frequency electromagnetic radiation called microwaves, which make certain food molecules (water, sugar, and fat) vibrate very fast. The friction between these molecules is what produces heat and cooks the food. Think of how you rub your hands together to keep warm when it’s -30° out – that is what’s happening to your food at a molecular level in a microwave oven.
Understandably, one might raise an eyebrow at the words, ‘electromagnetic radiation.’ But fear not! Microwaves do not carry the same health risk as ionizing radiation like x-rays. The waves cannot pass through the metal walls of a microwave oven, and they leave no traces behind in your food.
These microwaves form peaks and valleys as they bounce around inside the oven. If two peaks bump into each other, they generate heat, but if a peak hits a valley, they cancel each other out. That’s why most microwaves have a turntable in the middle: it helps ensure the food does not sit in a ‘cold spot.’
The other thing you should know about microwaves is that they are quite short. In fact, they can only reach about an inch and a half into your food. It’s the molecules in the outer layer of food that generate heat; the middle portion warms up through contact with the edges, which takes a bit longer.
The takeaway from this lesson:
- Unlike a gas or electric oven, microwave ovens generate heat by use electromagnetic waves.
- Microwaves have warm and cold spots, which is why most newer models have a turntable.
- Microwaves only reach about an inch and a half deep into the food, and the rest heats up through conduction.
Knowing this, you can begin to see how microwave cooking is different from cooking in a convection oven. There is a way to cook food evenly in the microwave every time, but before we get to that, we should tackle the topic of ‘microwave-safe.’
Lesson Two: Which Materials are Microwave-Safe?
The rule of thumb when it comes to microwave cooking is this: if the packaging doesn’t contain words or symbols indicating it is microwave-safe, don’t put it in the microwave. Beyond that, here is a brief guide as to which materials are microwave-safe:
- Glass/ceramic: Unless the packaging states otherwise, glass and ceramic containers are safe to use in the microwave. Neither is affected by radio waves at that frequency and thus don’t become excessively hot in the microwave.
- Plastic: A plastic container that has a microwave-safe icon or the words “microwave safe” has met the FDA’s standards and specifications for use. So long as it is free of cracks or scratches, a microwave-safe plastic container is safe for the microwave However, many people are wary about the possibility of chemical ingredients in plastic leaching into the food; in that case, there’s nothing wrong with sticking to glass or ceramic.
- Paper: Most paper plates, paper towels, and napkins are safe to use in the microwave, but some have a thin plastic coating, so it is best not to place them in the microwave unless they have the microwave-safe label.
The following materials are not microwave-safe:
- Metal: Microwaves bounce right off metal, so metal trays and bowls are ineffective for microwave cooking. Tin foil is also out of the question, since any thin or pointed metal edges will allow electricity to arc and potentially damage the appliance.
- Styrofoam: Although some Styrofoam containers do have the FDA stamp of approval, these vessels can scratch and crack easily, so they are not the best choice.
- Disposable plastic: Plastic jars, yogurt tubs, and other disposable containers are not appropriate for microwave use.
When in doubt, ceramic and glass are the two most reliably microwave-safe materials.
Lesson Three: How to Cook Food Evenly in a Microwave
The most common problem people have with the microwave is getting food to cook evenly. The solution? Maximizing the reach of those electromagnetic waves.
We know that microwaves heat create heat by vibrating water, sugar and fat molecules. We know microwaves are short, and that microwave ovens tend to have hot spots and cold spots. Knowing this, we can arrange the food in a way that ensures an even distribution of heat.
You can summarize the fundamentals of microwave cooking in five points:
- Instead of placing food in the center, spread it in a circle around the outer edge of the container or plate. The more you spread it out, the better. This makes it easier for the microwaves to reach in and create enough friction to heat the food evenly.
- Place a cover over the food to keep water from evaporating. This will help prevent the food from drying out. If possible, leave a small gap uncovered to steam escape as it cooks.
- When heating a lot of food at once, try cooking in one-minute intervals instead of a single long cycle. Before each interval, mix the food with a spoon to help even out the heat distribution.
- Put the container on the outer ring of the turntable to keep the food moving while it cooks.
- Let the food sit for a minute after it comes out of the microwave. This will allow the heat to continue to spread via conduction before you dig in.
The specifics will vary depending on the model of microwave oven and the kind of food you’re cooking.
But these five points will go a long way to ensuring microwave cooking perfection!
Hungry for more delicious microwave facts? Check out our other offerings:
- 5 Microwave Myths Debunked. Do microwaves really zap the nutrients out of your food?
- How to Determine the Best Microwave to Buy. Learn why size matters.
- How Does Your Danby Microwave Work? Magnetrons, how do they work?
- The Top Recommended Microwave Recipes. Three words: Sweet potato chips.