Have you ever gone to warm up some leftovers in the microwave but hesitated before hitting the start button? You picked a ceramic bowl, assuming it would be fine, but is it? Are ceramic bowls microwave safe?
There are three different types of ceramics; earthenware, stoneware, and porcelain. All ceramics are made with clay, hardened with fire, and then decorated. They are all vital to our everyday lifestyle, but they are not the same.
KitchenAid discusses ceramic vs glass bowls
Generally, ceramics are all extremely heat resistant. Often you will find things like coffee cups, dinner plates, bowls, and even pizza pans made from ceramics.
Most of the time, ceramic cookware is fine to go in the microwave. The only exception is if it is lined or rimmed with metal - so always check carefully. If there is a label, read it carefully to know if your ceramic bowl is safe to go in the microwave.
Note: If you're curious, we also have an article about whether or not your ceramic ware is oven safe.
Ceramics can be defined as an inorganic, non-metallic material that is baked at high temperatures until it gets solid. The exact temperature will determine if a piece ranks as one of the three ceramic types.
A ceramic bowl in a microwave oven
Earthenware is a type of ceramic that has not been heated to vitrification, leaving it much more porous than its glass-like sisters. As a result, it is usually coarse, with a more natural, rock-like texture. These dishes typically have to be glazed or otherwise sealed if used for liquids, or else they will leak.
After baking at a higher temperature, stoneware is more dense and durable than earthenware. It is naturally much smoother and has vitrified so that it is waterproof. Stoneware makers can glaze it for decorative purposes, but it’s not necessary.
Often mistaken for glass, porcelain bakes at a much higher temperature than other types of ceramics. The result is shiny, smooth, solid, and sometimes slightly translucent. This type of ceramic is commonly known as “fine china” since it was first discovered in China in 1600 BC.
There is no one-answer-fits-all for ceramics due to the many different types, seals, and decor styles. You'll want to check to be sure, but more often than not, you can microwave ceramic bowls as most are safe for microwave use.
Many dinnerware options will have a label somewhere on the dish telling you if it is microwave safe or not. Sometimes this can be a simple symbol, something that may look like a microwave, or three squiggly lines to symbolize heat.
A plain white ceramic bowl - which may or may not be safe for microwave ovens
Any ceramic mugs or food containers that don't have the microwave safe symbol should be assumed to be non microwave safe dishes and shouldn't be used for microwave cooking. The only exception is if the manufacturer certifies your product is microwave safe. Find the original packaging for your ceramic container or get in touch with the manufacturer to try to determine if the container can go into the microwave.
Look for a microwave safe symbol on your ceramic plate
Before microwaving your microwave safe ceramic bowl for an extended period, try placing a cup of water inside it and heat for one minute. If the bowl is hot to touch when done, but the water in the cup is not, your dish is not microwave-safe.
If you can place your bowl in the microwave for one minute and have it come out slightly warm or cool to the touch, and the cup of water is hot, your dish is microwave-safe.
Ceramics often can be mistaken for glassware due to their fragility and appearance. However, glassware is a non-crystalline structure, while ceramics are often crystalline, or at least partly so.
In dishware, you can usually tell if something is glassware because it is translucent, whereas ceramics are opaque. Both can be misleading when painted, however, so check the label if you want to know definitively if something is glass or ceramic.
Glassware is almost always microwave-safe, but always check the label or use the test explained above if you are unsure.
The FDA regulates safety standards and performance for all microwaves, so if something is microwave safe for one, it is microwave safe for them all. Thus, the ability to mark something as safe or unsafe to be used in the microwave.
Plastic dishes are at the most risk of being unsafe in the microwave because they will melt. There are types of plastic, such as high-density polyethylene, that are safe because they are more durable and stay cool while being nuked.
Even microwave safe ceramics and glassware both have the potential to be dangerous in the microwave at extremely high temperatures. However, it is unlikely that they will reach such temperatures while warming up food.
One way to ensure that you and your microwave safe dishes stay safe in the microwave is to nuke things in small intervals. Put your dishware in the microwave for 2-3 minutes, then take it out to sit or stir it before placing it back in.
If your ceramic dish is hot to the touch after being in the microwave, let it cool enough to grab before placing it back in. Always use oven mitts or a potholder when handling hot dishes.
Depending on what it is made of, a non-microwave safe dish may melt, catch fire, shatter, or break. Certain types of plastic may not appear damaged while being nuked but can release harmful chemicals into your food.
Additionally, even microwave-safe bowls run the risk of breaking if they are too cold before going in. It is a good habit to let any refrigerated or frozen dishes set at room temperature for a few minutes before being placed in the microwave.
If you have deemed your ceramic dish to be microwave safe, the odds are that it is also dishwasher safe. Likewise, if you’ve safely placed your ceramic dishes in the dishwasher, it is likely microwave safe. But, once again, always check the label to be sure.
Earthenware especially can be more delicate than other ceramic options and tends to absorb water. If you are not sure about a particular dish, it may be best to hand wash it, just in case.
Another thing to consider is that if your ceramic dishes are painted or glazed, especially if done by hand, don't put the dishes in the dishwasher. The dishwasher may not only slowly strip away that coating, but it could create a dangerous situation if the product is lead-glazed. If you want your ceramics to last for years, a gentle hand wash is the best option.
When using a microwave oven, it’s crucial to know how they work. These instant ovens produce actual microwaves, a form of electromagnetic radiation that causes the food to vibrate so fast it gets hot.
The microwave radiation produced by is non-ionizing, so making it slightly less dangerous than other forms of radiation in small doses. It is also produced in very small amounts, thanks to FDA regulation.
While most microwave-related injuries are due to burns, there have been instances of radiation injury if someone is around many microwaves at once for a long time.
Here are several tips you can follow to make sure you are using your microwave safely and to avoid injury, a fire, or damage to your microwave.
It may seem like common sense not to place anything metal into your microwave, but we’ve all been there. Maybe you’ve tried to warm up a fast-food sandwich with foil lining or thrown a ravioli can in without thinking.
So, why does your microwave accept anything from plastic to glass to ceramics but throw a fit for metal? The problem is simple. Your microwave creates vibration, and with metal, that vibration creates sparks.
Many different types of metal can be dangerous in a microwave. If you mistakenly do so, turn off your microwave right away. If it appears to be functioning with the door open or any other important piece is damaged, unplug the cord.
In the event of a fire, if you can safely reach your fire extinguisher, do so and follow the directions to put out the fire. Never touch metal that has been in the microwave as it will be extremely hot.