Can you Microwave Ceramic? | Dos and Don’ts and Our Full Guide

Cooking with a microwave oven, sometimes, can be confusing whether something is microwavable or not. Did you know you can cook an egg in a microwave?

One would think that it is pretty straightforward, but there are actually different types of dishes that are left unlabeled and may or may not be microwave safe. In addition, there are different types of ceramic that may or may not be safe.

In this article, we will go over the different types, as well as what materials you can use for cooking inside a microwave (and what you can't), as well as how to test dishware if there aren't any labels included. We included easy and practical tips to help navigate the options of how to best microwave ceramic and another similar type of dishware.

Dos and Don'ts In Microwave Cooking

Microwaves (see top convection ovens) are an everyday part of our lives, but it doesn't hurt to get a primer again on how to best use them. Below are some quick do's and don'ts when microwave cooking.

What Should I definitely Not Put in a Microwave?

Here is a list of dishware materials you definitely should not put in a microwave (check out medium power microwaves). It's not exhaustive, but it is broad enough to get the point across:

• Dishware with metallic paint

• Dishware with decorative metal trim or a metal rim

• Wire twist ties

• Take-out containers with metal lining or handles

• Aluminum foil

• Metal utensils

• Clay dishware with a shiny or transparent glaze (often an indicator of lead in the glaze)

• Handmade artisan dishware

• Dishware with bright and vibrant colors on the inside surfaces

• Antique dinnerware (Certain colorful pre-1960s mugs get their colorful glaze from uranium and other radionuclides that give off radiation. The EPA [Environmental Protection Agency] advises highly against using them for food or drink.)

• Highly decorative and shiny dishware

• Cold food storage containers

• Brown paper products (white paper plates and products is ok)

What are Ceramic Dishware and Cookware?

Ceramics is a large category but includes brick and earth-based goods and ceramics made using clay or even porcelain, which is often more costly. They are produced by hand or manufactured en masse. Ceramic dishware includes plants, bowls, or cups made of ceramic. The heating process hardens the earth-based material so that it is strong and durable.

In cookware, ceramic coating or cookware that is all ceramic is also considered a safer non-stick alternative to Teflon. Teflon is the material most pots and pans are made of that make them non-stick without oil. A word of caution: the ceramic coating is different than cookware that is all-ceramic. The coating can be damaged easily, which can bring the metal in direct contact with food.

For ceramic dishes and dishware, the advantage of ceramic dishware is that it is often oven and microwave-safe. Depending on the quality, it is also expensive. Porcelain, for example, is considered an investment piece to your home collection when the time comes. It is usually very convenient to use like another ceramic dishware but beware of the more decorative pieces. Some include other materials and are not microwave safe.

Why use Ceramic for Microwaving?

A large variety of things can be used to cook food in a microwave. Some plastics, Pyrex, and some ceramic are all types of microwave-safe dishes and dishware. Major brands that sell similar microwave-safe dishware include Anchor Hocking, Duralex, Pyrex, Corningware, and Visions.

When dishes are made from ceramic, for example, they will not emit hazardous toxins when heated. In general, it is not recommended to microwave plastic; however, we all get lazy sometimes, and especially with take-out containers, as long as it is the right kind, we won't split hairs over the details.

On the bottom, look for the number with a recycle symbol around it. This tells you the type of plastic the container is made of. In general, avoid plastics with the numbers 1, 3, 6, or 7 on them. Microwave-friendly options will be labeled 2, 4, and 5. Ceramic, sometimes, is not so straightforward.

When Should I not use Ceramic Cookware in the Microwave?

Despite being in the same category, ceramic pots and pans should not be used in microwaves. As mentioned before, ceramic cookware often only has a ceramic coating only. Its base being metal, it is not considered appropriate to microwave.

Most ceramics, often glazed forms, have lead in their glaze. Avoid this as the microwave could melt the glaze, contaminating your food or drink. When choosing a ceramic mug that you want to be able to use in the microwave, look for a mug with lighter colors. The dark glazes that are used on ceramic mugs have higher levels of manganese. While this doesn’t make the mug unsafe to microwave, it probably makes the mug hotter in the microwave.

In addition to the glaze, some decorative mugs may include things you cannot microwave, like pieces of metal. Be sure there are no stray pieces of metal when investigating your dishware. Even a small piece can be trouble. Avoid dishware with metallic trim.

The Microwave Safety Symbol

Ceramic containers and plates that are microwave-safe typically have labels to avoid confusing them with other kitchen appliances or dishware. This symbol is usually a series of wavy lines sometimes shaped like an ‘M’ and can be a square or round symbol.

It also often has a microwave-safe label that says "microwave safe.' If you do not see any sign that the dish can be a microwaveable device, then it would be best to avoid using it until you find relevant information about the product, such as on the manufacturer's website.  

Often, it is labeled on the bottom of the dish whether it is microwave-safe or not, and on the product box, there is often a symbol to represent a product being microwave safe. Sometimes, both show up in the same place.

Can You Microwave Ceramic Mugs?

Most everyone has a favorite coffee mug, and chances are it is glass (or a mix of materials) or ceramic. Microwaving ceramic mugs are usually ok. If microwaving water for tea at room temperature, just remember to handle it with care. A mug of hot water may not be steaming, but coming out of a microwave, the mug may have absorbed most of the heat first.

Our only caveat to this is to make sure that if you use a mug that is artisan or was handmade, make sure the glaze or clay material used is food safe.

How to Test if Something Is Microwave Safe

Most dishware will say whether it is microwave-safe or not, but on the chance, it's not, there are other ways to check. Non-microwaveable materials can melt, crack, or be otherwise damaged in the microwave. It’s a good thing to test a dish to be microwave-safe before using it. Some materials can also leak dangerous chemicals into your food or cause larger accidents like fires, or damage the microwave itself (in case that happens, take a look at budget-friendly ovens or these even more affordable microwaves).

Microwave a microwave-safe cup with the dish in question. To test if a dish is microwave safe, you can microwave it with a cup of water for a minute on high heat or high power. Find a glass or cup that is microwave safe, and fill it up to three-quarters of the way with water.

The test will be done using touch to the dish and how cool it is after being microwaved. A dish that doesn't microwave-safe will have absorbed the heat from the water rather than conducting it to the food being served on it.  To be clear, the dish is not safe for the microwave if the dish is warm and the water is cold. However, the dish is microwave-safe if the dish is cool and the water is warm. A cool dish means it doesn’t absorb heat. If the spot feels warm, it is still okay.

Conclusion

Modern ceramic today is mostly all microwave safe, unlike older antique ceramic and handmade ones. Usually, they will include a symbol and label that says it is safe to use in high temperatures, like an oven or microwave. When left unlabeled, it is better to be safe than sorry and test your dishware before using it.

There are some blatantly obvious things you definitely should not heat in your microwave, like most materials used for take-out. Just to be on the safe side, always transfer that to a microwave-safe bowl or plate before eating. It only takes a few seconds and is better safe to do than be sorry later.