If you’re like me, you can’t start your day without a good ol’ cup of coffee! Sometimes I make it at home, but often I’ll stop by Starbucks on my way to work! The issue with this is I will get a Venti, not drink it all at once, and then it gets cold. I like to drink my coffee hot!
So, I started thinking, can you microwave a Starbucks coffee cup? The cup already has hot coffee in it, so it’s designed to hold liquids. Therefore, it MUST be ok to microwave! WRONG! Technically, you CAN microwave a Starbucks coffee cup, but you shouldn’t. The main reason is leaching chemicals each time you heat the cup up and degradation of coffee in terms of taste.
I did an experiment by microwaving my Starbucks coffee cup over and over throughout the day. And drank it. I’ll disclose the results below and we’ll look into more why you shouldn’t microwave a Starbucks coffee cup.
Read on to learn more!
What Are Starbucks Cups Made Of?
When you order a hot coffee from Starbucks, whether it be a regular coffee, a mocha, or a latte, you will receive the same kind of cup. Starbucks to-go cups are made of paper with a plastic lining on the inside. This double-walled design keeps coffee hot and allows the exterior to remain dry. The paper cup doesn’t absorb the liquid! This makes it very practical in durability and price for both customer and business!
If you have ever tried to put a hot liquid in any paper cup before, you probably noticed it leaks right through. This plastic lining that Starbucks uses in their cups prevents this!
What Happens if You Microwave a Starbucks Coffee Cup?
Many sites I’ve looked at will say that the cup will melt due to the plastic lining on the inside. Or that the glue and adhesive holding the plastic on the paper will melt.
My experiment on Microwaving a Starbucks Coffee Cup
My experiment went like this. I ordered a Venti regular black coffee. I microwaved it every couple hours throughout the day to warm up the remaining coffee in the cup. And I’m the kind of person who likes her coffee HOT. So, I use a high setting and microwaved my coffee in minute intervals until hot.
Results: The cup stayed intact. Nothing on the inside melted. Other than a small taste change due to the coffee being reheating several times, the cup held up very well in the microwave.
I haven’t been able to find anything on the Starbucks website, so I emailed Customer Service to learn more. I will post the response once I receive it!
Can You Microwave a Starbucks Coffee Cup?
The answer is no, you shouldn’t microwave a Starbucks coffee cup. Starbucks clearly states on their cups “Do Not Microwave.” However, they really do not say why. And as I’ve shown with my experiment, the cup held up very well.
We can come up with a few reasons you shouldn’t microwave a Starbucks coffee cup.
Starbucks uses a polyethylene plastic lining on the inside of their cups. While this is perfect for keeping the hot liquid inside the cup, it’s not the best material to put in the microwave. According to a study done in 2011, the majority of plastics, even if they are BPA-free leach toxins and chemicals into the food or beverage when heated. These toxins are known endocrine disruptors and can mess with healthy hormone function.
Potential of Melting
Polyethylene plastic is a commonly used adhesive. The lining inside the Starbucks coffee cup is not only plastic but a glue. Exposed to heat could potentially melt the glue and get in the beverage.
So, final answer? Even though my experiment didn’t show any signs of physical deterioration in the cup or melting, we recommend to always follow the guidance of the manufacturer. We actually try to avoid putting any plastics in the microwave!
Can You Put Starbucks Reusable Cups in the Dishwasher?
The paper Starbucks cup you get with your to-go coffee should not be put in the dishwasher. These cups are intended to be single use only, although I have definitely kept them around a little longer. If you do wish to reuse these single-use cups, make sure to handwash them only!
- The plastic making up the inside lining of the cup has potential to melt if exposed to the heating element.
- The paper material of the cup will disintegrate. The cups are designed to hold liquid and not leak through due to the plastic lining that serves as a barrier. In the dishwasher, the entire cup is exposed to water.
Because Starbucks sells many different types of coffee cups, it can really depend! Let’s look at the different cups you can get at Starbucks and whether they are dishwasher safe.
- Ceramic Mugs– Typically hand wash only. Check bottom of mug to verify.
- Glass Mugs– Generally dishwasher safe. Put on top rack away from heating element.
- Plastic Tumbler- Dishwasher safe.
- Stainless Steel Tumbler- Dishwasher safe.
Can You Microwave Styrofoam Cups?
No, do NOT microwave Styrofoam cups!
Styrofoam is actually the brand name. What we call “Styrofoam” is actually a material called expanded polystyrene, or EPS for short. EPS is a type of plastic made from polystyrene that has been expanded by a chemical reaction with steam. This makes the plastic into a foam, which is why it is often called Styrofoam. EPS can be used in many different applications, such as packaging like single use cups we drink out of!
You should never microwave these Styrofoam cups! For two reasons:
- Styrofoam cups are not designed to be able to withstand heat. Exposing them to high temperatures for long periods of times can cause the cup to melt.
- When heated, polystyrene can emit the toxic chemical styrene, which has been linked to cancer.
Can You Microwave a Ceramic Coffee Cup?
Ceramic coffee cups are generally ok to microwave. Ceramic material can already withstand higher heats due to how it’s made.
To check to see if a ceramic coffee cup is microwave safe or not, check the bottom. There will be a label or words that say “microwave-safe.”
Ceremic coffee cups that should never be microwaved:
- If there are any visible cracks
- If there are any metallic linings or patterns with ink
Can you Microwave Glass Coffee Cups?
Glass coffee cups are generally ok to microwave, especially if it is tempered glass. Tempered glass is created by exposing the glass to extreme temperature changes during the production phase.
To be on the safe side, only microwave glass coffee mugs that have a microwave-safe symbol or the words “microwave-safe” on the bottom.