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Can You Microwave A Starbucks Paper Cup?

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Do you have cold coffee leftover from the morning and wonder if it is safe to microwave a Starbucks paper cup? Whether you ordered an americano or caramel macchiato, microwave Starbucks cups to reheat your favorite hot beverage with a few simple steps.

A Starbucks paper cup is made with wax and plastic coating inside that is designed to hold hot beverages, but not necessarily intended to reheat or cook with. So if you microwave a Starbucks paper cup, the heat can melt the inside coating and also the glue that holds the cup together.

Heating the cup lining could leach wax, plastic or adhesives into the beverage. Furthermore, you may experience leaks from the sides or bottom of the cup if overheating affects the bond that holds the cup together.

In general, these are the exact same reasons why it is not recommended to microwave a paper cup. If you have been throwing away cold coffee leftovers, save your cup of joe learn the best way to microwave coffee in a Starbucks paper cup. 

Is it bad to microwave Starbucks cups?

There are safe ways to reheat coffee in the microwave. Starbucks paper cups, especially the lining and glue part, are not designed to hold up to the high temperatures involved with the heating process.

Microwaves use electromagnetic radiation to agitate atoms, which creates friction that ultimately heats water molecules. The microwave does not heat or cook foods evenly.

If not done properly, then part of the paper cup can be burnt and melted. Therefore, it’s not a good ideas to microwave Starbucks cups to reheat your favorite coffee. 

The extreme heat and sudden changes in temperature can cause the paper cup to warp and seep contaminants into the hot beverage. 

Here are some of the reasons why it is bad to microwave Starbucks cups:

  • Starbucks cups are coated with plastic and wax to make it waterproof.
  • Microwaving may leak toxic contaminants into the hot beverage. 
  • The glue that holds the cup together can melt in the microwave, and your cup may start leak from the bottom and sides.
  • The taste of coffee will change due to paper burns, softened inside coating or melting glue.

If you are looking for another alternative, some Starbucks plastic cups can be heated in the microwave. Make sure to heat no more than 40 seconds in the microwave and stir between each interval. 

Are paper coffee cups microwave safe?

When you put any paper cup in the microwave, the contents tend to reheat very quickly. However, not all paper coffee cups are designed to be microwave safe. 

Paper cups are perfect for single-use, and are also easily decomposable. As a result, they have become convenient for everyday use and people have naturally gravitated to heating paper coffee cups in the microwave. 

Because the heating temperature in a microwave escalates rapidly in short period of time, even a few seconds can be too much for a paper cup to handle. The intense heat can cause the adhesives and inside coating of a paper cup to melt or even burn. 

When looking for microwave safe paper cups, you will need to consider how the paper cups are held together; and also, factor in what the inside coating is lined with. 

Why do paper cups say do not microwave?

Microwaving paper cups are quick solution to reheat any beverage in a disposable single use container. However, the risks can outweigh the rewards and the results can be harmful for many reasons.

Same goes for a Starbucks paper cup, you may find that most paper cups say “do not microwave.” This is because the cups are made with a thick paper or cardboard material that requires glue to hold the cup together and a wax coating to keep liquid inside the paper. 

Unfortunately, these materials aren’t suitable for heating in the microwave. The intense bursts of extreme heat directed at the paper cup can melt the wax and adhesive glue, which can combine with the hot coffee inside the paper cup. 

Chemical contamination is the primary concern, and that is why paper cups say do not microwave. Furthermore, the integrity of the cup design can be compromised if the glue melts and the cup could leak or completely collapse.

Things to know before microwaving Starbucks paper cups

Coffee is typically enjoyed hot, unless you are drinking an iced coffee or blended Frappuccino. What if you have leftover coffee that you didn’t finish while the drink was still hot, can you microwave a Starbucks paper cup to reheat your beverage?

There are a few considerations to make before microwaving a paper cup. Can the paper, inside lining or glue withstand the microwave temperatures required to heat up the contents? 

There are alternate options you should know about before microwaving Starbucks paper cups. Use this method to reheat your beverage the right way.

  • Transfer the drink into a microwave safe cup.
  • Reheat the beverage using short, 30 second intervals. 
  • Stir the contents and test the temperature during each length of time.
  • Use caution when removing the hot container from the microwave after the beverage has reached the desired temperature.

If you have no option and must proceed with microwaving a Starbucks paper cup, then use caution and follow these simple tips:

  • Remove the lid of the cup.
  • Place the Starbucks paper cup inside the microwave. 
  • Set the power level to a medium setting.
  • Heat for 1 minute increments.
  • Stir the reheated beverage between each interval
  • Test the temperature with caution. 
  • Carefully remove the hot cup from the microwave.

Microwave is known for uneven heats with large temperature differences in the same container. In addition, it is really unpredictable to determine how hot the container of liquid is going to be when you reach in to grab hold.


Sadly, Starbucks paper cups are not microwave friendly. The temperature produced inside a microwave can damage, warp or melt the paper cup lining and adhesive glue used to hold the cup together.

First of all, the paper cups have a very thin lining that can’t hold up to extreme heat. As a result, the quality of the reheated coffee is not guaranteed because it may be affected by contamination from the toxic components of the cup.

So, if you want to reheat your Starbucks coffee, you should transfer the contents from the paper cup to a microwave-safe container, cup or mug. Reheat in short 30 durations and stir the beverage between each interval.

If you have had success with microwaving a Starbucks paper cup, then you should have nothing to worry about. However, if you are evaluating the safety of using a paper cup in the microwave moving forward, then it is probably best to consider using a ceramic or glass cup that is labeled as “microwave safe.”

Is a Starbucks cup microwave safe?

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