Can you microwave starbucks cups?

You may think that Starbucks cups are microwaveable since they are made of paper, but unfortunately, they are not. While most of the mug is made of a thick cardboard-like material, a plastic lining on the inside makes the mugs dangerous to heat in a microwave. Most paper cups have some sort of lining, which means that virtually all paper cups are not safe to microwave, not just Starbucks cups. Can you microwave starbucks cups?

If you want to reheat Starbucks coffee, you must first transfer it to a microwave-safe container. It may seem counterintuitive that a mug designed to hold hot beverages cannot be microwaved, but it is true. In this article, we’ll explain why Starbucks mugs aren’t safe to use in the microwave.

Microwaves, how do they work?

We won’t turn this into a physics lesson, but a little background knowledge about how microwave ovens work will help us understand why microwaving paper cups is a bad idea.

Unlike traditional ovens that use hot air to cook food, microwave ovens use microwave radiation to heat things from the inside out. Radiation is a scary word for many people, but microwave radiation is completely safe. The light that we see with our eyes is radiation, and microwave radiation is less energetic than visible light.

can you microwave starbucks cups

When an object, such as a piece of food, is exposed to microwave radiation, the water molecules in the food vibrate in response to the microwaves and heat up. The wavelength of the microwaves used in microwave ovens is specifically tuned to excite water molecules. Anything that contains water can be heated in the microwave, and conversely, if something does not contain any water at all, it will not be heated in the microwave.

Why aren’t Starbucks paper cups safe to use in the microwave?

Now that we know a bit about how microwaves work, we can start to see why reheating coffee in a paper cup isn’t such a great idea. The paper itself has some water content, making it susceptible to heating up and igniting in the microwave, but the most pressing concern comes from other parts of the mug.

Although starbucks cups are primarily paper, they also contain a plastic coating, wax, and glue. Paper cups are not waterproof, and without a liner, they will get soggy and spill after just a few minutes. To combat this, companies add plastic liners that hold the liquid inside. Microwaving a plastic-coated mug is dangerous, as the coating could melt, causing physical harm if the melted plastic touches your skin, or chemical damage if it seeps into your coffee.

can you microwave starbucks cups

You might think that as long as you don’t overheat your Starbucks cup, you’ll be fine, but that’s not true either. Even a quick 10-15 second stint in the microwave can heat the glue holding the mug together enough that it starts to fail. At best, you’ll have to deal with a small leak, and at worst, you could end up burning yourself on hot coffee.

Can reusable Starbucks cups be heated in the microwave?

starbucks sells reusable coffee cups and travel mugs that you can use in their stores for a small discount. These mugs are usually made of plastic or ceramic, making them more microwaveable. However, it is important to check if the mug has a microwave-safe label before using it in the microwave.

can you microwave starbucks cups

Even some mugs that appear to be microwaveable based on the material are actually not safe for other reasons. If your mug has a rubber gasket or metallic paint, it can’t be used in a microwave and it can be hard to tell just by looking at the mug. Your best bet is to search for a tag and opt out if you can’t find one.


Most people know that metal isn’t safe to use in the microwave, but they don’t realize that paper cups aren’t safe either. It’s natural to assume that a mug designed to hold hot beverages could withstand the heat generated in a microwave, but due to the inside-out heating design of microwave ovens, even containers designed to hold hot beverages can break in a microwave.

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