Microwaves are a staple in most kitchens these days. They provide a quick and convenient way to heat up leftovers or prepare a quick meal. Plastic Tupperware containers are also common in many households.
But can these two kitchen tools safely be used together? Let’s take a closer look at whether you can put plastic Tupperware containers in the microwave.
How Microwaves Work
To understand if Tupperware can go in a microwave, it helps to first look at how a microwave works. Microwaves generate electromagnetic waves that cause water molecules in food to vibrate, creating friction that heats the food.
This is why microwave-safe cookware needs to either contain no water molecules for the waves to heat, or be designed to absorb and distribute the waves evenly.
Metals are unsafe in microwaves because they reflect the electromagnetic waves rather than absorb them. This can create electrical arcing and sparks and damage the appliance.
It’s also why metal cookware becomes dangerously hot in the microwave, while glass, ceramic, and plastic containers designed for microwave use remain cool to the touch.
Is All Plastic Tupperware Microwave-Safe?
Now that we know why metals are microwave-no-nos, what about plastic? Here’s the general rule of thumb: If the Tupperware is labeled “microwave-safe,” it should be okay to use in the microwave. However, if it’s not labeled as such, it’s better to be safe than sorry.
There are a few reasons why some plastic containers aren’t suitable for microwaving:
- They may have components that reflect microwaves rather than absorb them. This could include metal paints or small metal flecks in cheaper plastics.
- They may not withstand the heat generated by food inside them, even if the plastic itself doesn’t absorb much heat. This could cause warping, melting, or the leaching of chemicals into food.
- Cheaper plastics may have lower melting points and contain more harmful chemicals that can leach into foods during microwaving.
Signs of Unsafe Plastic Containers
If your Tupperware isn’t labeled microwave-safe, here are some signs it could be unsafe to use:
- It becomes warped, melted, or discolored after microwaving.
- It has stains from food that leaked into the container during microwaving.
- It has metal on it, like metal paint or metal bands around the lid.
- It smells strongly of chemicals after being microwaved.
- Food tastes odd or unpleasant after being microwaved in a container.
- You’re uncertain of the material (it isn’t labeled).
If you notice any of the above, stop microwaving that container!
Safest Choices for the Microwave
To be sure your Tupperware is harmless, look for containers labeled microwave-safe. Glass and ceramic with no metal are also good choices. Here are some of the best microwave-safe Tupperware options:
- Glass – Glass is great for microwaving. It’s non-porous, so stains won’t set in, and it distributes heat evenly.
- Microwave-safe plastic – Look for the microwave-safe label and avoid plastic with any metal. The safest bet is BPA-free plastic.
- Microwave-safe silicone – Silicone is ideal since it’s durable, stain-resistant, and less likely to absorb stains and smells.
- Ceramic/porcelain – These are durable and distribute heat well. Ensure any decoration is microwave-safe.
- Microwavable silicone covers – These reuseable, often brightly colored covers transform non-safe containers into temporary microwave-safe ones.
Can You Microwave Other Plastics?
Besides Tupperware, other plastics find their way into our kitchens. Which of these are safe for the microwave?
- Plastic wrap/cling wrap – Surprisingly, most household plastic wraps are microwave-safe. Double check the box to be sure. Avoid letting it touch food, as it can melt.
- Zipper storage bags – Those labeled for microwave use are generally fine, but avoid reusable bags without a microwave-safe label, as well as cheap bags.
- Plastic plates/cups – Disposable plastic dishware is usually okay, unless it is very cheap or visibly damaged. When in doubt, don’t microwave.
- Tupperware lids – Lids often aren’t labeled. If the base is microwave-safe, the lid should be too. Put the lids microwave-safe side down just in case.
- Melamine – Do not microwave! Melamine can leach harmful chemicals into food when heated.
FAQ About Microwaving Plastic
Here are answers to some frequently asked questions about the safety of microwaving plastics:
Is it safe to microwave any plastic container?
No, only plastic marked microwave-safe should be microwaved. Containers not labeled for microwave use may melt, warp, or leak chemicals.
Can I microwave plastic bags?
If labeled for microwave use, plastic storage bags are generally safe. Avoid reusable plastic bags without a microwave-safe label.
What could happen if I microwave plastic that’s not microwave-safe?
The container could melt, warp, discolor, absorb food stains and smells, or leak harmful chemicals into foods during microwaving.
How do I know if my old Tupperware is microwave-safe?
Check if it is labeled microwave-safe. If unsure, look for signs of wear like stains, odors, and warping after microwaving. If so, discontinue use.
Is it safe to microwave plastic wrap?
Yes, most household plastic wraps are fine for microwave use, but avoid letting them touch food as they can melt. Check your plastic wrap box to be sure.
Can plastic plates or cups go in the microwave?
Disposable plastic dishware is generally considered safe, unless it is cracked, scratched, or very cheap plastic. When uncertain, don’t microwave.
What type of plastic is the safest for microwaving?
Microwave-safe plastic labeled BPA-free is your best option. Glass and ceramic containers are also great microwave-safe choices.
The Bottom Line
Microwaving plastic that’s not designed for microwave use can be unsafe. The plastic could melt, release chemicals, or absorb food odors and stains.
To play it safe, only microwave plastics are labeled “microwave safe.” Additionally, reach for glass, ceramic, and silicone products labeled for microwave use.
With the proper microwave-safe containers, you can safely leverage your microwave to save time cooking and minimize clean-up.
Hi, I’m Julie, the passionate foodie and founder of Juliesfamilykitchen.com. I created this blog out of a drive to prove someone wrong, and then I realized how much I truly enjoy cooking and trying new recipes. In my free time, when I’m not running around after my kids or spending quality time with my partner, you can usually find me in the kitchen experimenting with new dishes.