Why Can’t You Microwave Starbucks Cups? Know Here!

Last Updated on: 20th July 2023, 08:00 pm

You have one super important presentation coming up and decide to pull an all-nighter. You go to the kitchen, complaining and plan to reheat the Starbucks you got earlier today in your microwave. But hold on, you can’t microwave Starbucks cups!

But wait, Why Can’t You Microwave Starbucks Cups in the first place? The answer lies in the materials of the cup, the ruined taste of the coffee.

First off, Starbucks themselves do not promote heating their coffee cups (unless it is explicitly mentioned that you can heat them).

Secondly, the leaking of materials increases the toxicity and ruins the taste of the coffee in question. But there’s much more to reheating these cups. Let’s find out!

Starbucks cups refuse you to microwave their cups out of corporate liability. Beyond that, why can’t you still do it? Because it ruins the taste jumbles up the materials in and around the cup and poses serious toxicity. So what can you try instead? Microwave safe materials and ceramics Starbucks cup that’ll keep you and your coffee safe.

And if you don’t want to microwave, you can always switch to the good old-fashioned stove heating!

Why Do Starbucks Cups Say Not To Microwave?

If you have ever turned your Starbucks cup upside down to see what’s written, you would see the “DO NOT MICROWAVE” tag on the outer edge. But why can’t you microwave them?

Tell me, can you microwave plastic? Not always. The inside of Starbucks paper cups are made of a lining of wax and plastic.

Even though this plastic can safely hold your hot cappuccinos and lattes, it can not tolerate the microwave heat.

A famous paper cup manufacturer, Eco Products, says that microwaving paper cups can cause the glue of the lining to loosen and leak onto the fluid inside the cup, and if the heat from the microwave is too high (in case you want the reheating to be done quickly and increase the temperature), the cup might catch on fire.

And it is not just the glue and the plastic, there are other components making the cup that are not microwave-safe.

A major one of that is the ink that is used to write on these paper cups, which of course you noticed Starbucks cups have too.

Check Out: How Ideal are Starbucks Oven for Cooking

So, Why Can’t You Microwave Starbucks Cups?

Why can’t Starbucks cups be microwaved? Because they say not to. But what if there was no warning sign telling you “DO NOT MICROWAVE” under the cups?

Would you still proceed to do so since you have not been given any warning? Be it Starbucks cups or any other paper cups, the following are the reasons why you shouldn’t microwave them, whether or not the warning is mentioned.

  • Material Issues
  • Leaking and Toxicity Issues
  • Taste Issues
why can't you microwave starbucks ceramic cups
why can’t you microwave Starbucks ceramic cups?

Material Issues.

The first thing that should stop you from microwaving paper cups is the material it is made of. Do you see yourself microwaving books? No! Books are made of paper and lined with glue.

The fancy ones have even have ink and wax. What they don’t have like the coffee cups is the coffee inside.

Just how microwaving books would cause the elements to heat up and create a poor mix of gunk, microwaving your Starbucks cup too will mix all the materials depending on their heat retention.

So, why cant you microwave paper cups? Simply because, this is not a good material for reheating food or beverages.

Leaking and Toxicity Issues

As the materials of your glorious Starbucks cups melt, they won’t just sit. They’ll leak into the beverage that was inside the cup. And that isn’t bad.

What’s worse is you’ll drink it without realizing what got in.

This ill-mixture of a toxic blend will inevitably expose your body to harmful toxins and as such, should be avoided.

And the leaking won’t only happen inwardly. The leakage may happen outside the cup as the glue that holds together your cup will melt in heat.

Taste Issues

So you somehow managed it this far without causing any leak inward or outward (or so you mistakenly think).

You taste the coffee but why does it taste weird? Guess why! Something must have mixed with your coffee and changed it.

Yes, it was the materials inside that caused your coffee to turn up like a bitter concoction.

So even if you get away with microwaving Starbucks coffee cups without any hazard, don’t drink it because it tastes unbelievably bitter and poor.

Best Alternatives Methods Of Why Can’t You Put Starbucks Cups In The Microwave.

Guessing I have successfully managed to move you away from microwaving paper cups, what else can you do instead?

You can check out some microwave-safe materials and other Starbucks cups that you could try instead of paper cups.

Microwave-Safe Materials:

Not all plastics are like the lining of Starbucks cups. Some plastics can be microwaved too, just like some forms of glass and ceramics.

But if those plastic containers are as thin as the paper cups or are thinner in general than regular plastic vessels, these can melt and release toxins too.

Any food kept in them will in turn be intoxicated.

Now, there is an unofficial way to check for microwave safety, the 30 second DIY-test. What you can do is, place a cup of fluid, or preferably water in your microwave.

Set the temperature and wait as the microwave heats up.

Now after turning the microwave off, wait and bring out the cup safely. If you see that the cup is neutral/cold/at room temperature and the water inside has warmed up, your cup is microwave-safe.

But I don’t want you to go through trial and error on this, so always microwave containers that are tested for microwave-safety.

To understand that, check the care labels of any container or vessel that you will purchase. There will be a “Do Not Microwave” symbol (like you see in Starbucks cups).

Other than this, there may be a “Microwave” or a “Microwave Oven Safe” symbol. If you see this, you naturally know that this has been tested and is safe.

If you don’t see any of these, contact the manufacturer or seller before you chuck them into the oven to test.

Starbucks Cups That You Can Microwave?

Starbucks doesn’t just have plastic-lined paper cups. Besides those, there are other forms of reusable hot cups that they sell, such as the plastic cups and the Starbucks ceramic travel mugs, regular ceramic mugs,and glass mugs.

Which Starbucks Cups Can You Microwave?
Which Starbucks Cups Can You Microwave?

So if you desperately want to reheat your Starbucks coffee cup while avoiding increased toxicity or change of taste, make sure that they are made of either glass or ceramic.

But be careful while you toss the ceramic cups and mugs into the microwave.

Now, why can’t you microwave ceramic Starbucks cups just like that? Don’t get me wrong. Ceramic cups are still microwave safe. But only as long as they do not have any sort of metal gliding in the mugs.

Excessive heat may cause this metallic glide to crack, and give rise to health hazards.

Moreover, if the ceramic is thin, there is still the chance of this heating up and causing you to burn your tongue as you take the sip!

However, since the Starbucks travel mug has a thick lining, you will be good to go with the coffee experience as such ceramics have poor thermal conductivity and the heat from the coffee will not travel all the way through the mug to your hands. But remember not to put the lid of the mug in along with the mug!

As for the glass cups, you can do the thirty second test to see if the glass mug remains colder/less warmer than the water inside to understand if it is microwave-safe.

Then you can use it to reheat your coffee. But if it is explicitly mentioned that it is microwave safe (or not), don’t go for the DIY test.

Reheating Your Coffee For Make ti Taste?

Can You Microwave Starbucks Cups? Mostly, no. But do you have other options instead of microwave reheating? Entirely, yes!

Now that you have checked reheating Starbucks paper cups, and DIY-ing with their glass and ceramics mugs off your list, how else can you reheat your coffee?

The safest option is to try a saucepan. Pour your coffee into a saucepan and place it on top of a stove.

Wait as you see the coffee heat up and take it down after a minute or so, depending on what you prefer and enjoy!

If you don’t want to take the trouble of a saucepan, transfer your coffee to any microwave-safe borosilicate glass or ceramic cup, heat it, re-transfer it to your Starbucks cup and enjoy!

Some Safety Tips For Microwave Starbucks Cups

Some safety tips that could follow along the process include:

  1. Always wearing your gloves when you bring anything outside the microwave. If your glass or ceramic cup handle can not be held by your oven gloves, put the cup/mug on a baking tray or microwave-safe dish to bring it out.
  2. Never put your glass or ceramic cup with their lids on inside the oven.
  3. If you are not sure your glass or ceramic cup is microwave-safe, do the 30 second DIY-test. If after the test, your cups feel as warm or nearly as warm as the fluid inside, toss the idea of reheating in those cups/mugs.
  4. Do not put paper cups or dishes, Starbucks or not, into the oven.
  5. If your coffee smells or tastes different after microwaving, don’t drink it any more.

FAQs-Frequently Asked Questions:

Q. Can you put Starbucks reusable cups in the microwave?

The reusable ceramic cups by Starbucks are microwave-friendly. However, the reusable plastic cups are not. Hence, don’t put the latter in the oven.

Q. Why do coffee cups say do not microwave?

This is out of corporate liability. Since the cups aren’t made of microwave-friendly material, heating them and drinking them up may cause accidents and health hazards. So this is given as a warning to prevent customers from microwaving these.

Q. Can you warm up a Starbucks cup?

As long as it is microwave friendly like the Travel ceramics mugs, you can warm it up.

Q. Is it bad to microwave coffee cups?

Depends on what the coffee cups are made of. It is not bad to microwave glass or thick-lined ceramic cups.

Q. Can you heat up Starbucks cups in the microwave?

The Starbucks regular cups are not microwave-safe and hence can’t be heated up in the microwave.

Q. Why can’t I microwave my ceramic Starbucks cup?

This could be because of two reasons: the metallic gliding on the cup that could crack or melt in the microwave heat, or because of the thin walls that may heat up easily along with your coffee.


Hopefully, to know, Why Can’t You Microwave Starbucks Cups? So, is it safe to microwave Starbucks cups? Not always. It actually depends on the material of the cup and the safety label.

While Starbucks ceramics and glass mugs may sometimes be microwave-friendly, they aren’t always so.

And the paper cups are never microwave-safe. So refrain from doing so the next time you have a tough presentation.

Keep yourself awake by reheating your coffee in other microwave-friendly mugs. And if you have time, make yourself a fresh, new cup of hot coffee that is safe, not toxic at all and tastes a lot better than the reheated ones you were trying to make happen. Hope you rock that presentation!

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