Can You Put A Stanley Cup In The Microwave?

My Stanley Cup does a pretty awesome job of keeping my coffee nice and hot from the time I leave in the morning until I finally finish it off with lunch. 

But on those extra long days where I need a second (or third) cup to get me through to the evening, my coffee’s barely still warm. 

Which made me wonder, can I put my Stanley Cup in the microwave? 

Stanley recommends against putting your Stanley Cup in the microwave because there’s a chance it could damage your appliance or your tumbler.

If you have the soft matte Stanley Cup then putting it in the microwave will melt the soft exterior.

And besides, stainless steel containers are pretty awful at heating food and drink in the microwave anyway because they deflect electromagnetic radiation and heat slowly and unevenly. 

If you absolutely need to microwave your Stanley Cup, it won’t actually explode, set your house on fire, or release ancient spirits — no matter what you’ve been told. 

In reality, the most likely scenario is that nothing at all happens, aside from your coffee being warmed a bit slower than you’d like. That is unless you have the soft matte version in which case the exterior will melt.

If you put your Stanley Cup in the microwave with the lid on then there's also a high chance that the lid will melt in some parts.

Still, why take the risk? Just use a microwave safe cup or bowl if you can find one and pour your beverage into this, heat it up in the microwave and then pour it back into your Stanley Cup once it's hot.

Stanley Quencher H2.0 Tumbler Cup (Soft Matte) 40 oz

The grippable silicone finish offers a stylish, sophisticated look and a warm, velvety feel. Yet it’s dishwasher safe with all the durability you count on from Stanley. Beneath the unique Soft Matte finish is recycled stainless steel construction and double-wall vacuum insulation. And at the top is an advanced FlowState™ lid, featuring a rotating cover with three positions: a straw opening designed to resist splashes with a seal that holds the reusable straw in place, a drink opening, and a full-cover top for added leak resistance. 

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Is It Dangerous To Microwave A Stanley Cup? 

While you’ve probably heard time and time again that you should never stick anything metal in a microwave, it's mostly just an urban legend. 

In fact, most metal objects are relatively safe to microwave. 

The only real concern is when there are small gaps in the metal (like between the prongs of a fork), thin current-carrying antenna-like pieces of metal (like twist ties), or super thin sheets of metal (like aluminum foil) — which may spark or heat up excessively and start a fire. 

Large, rounded metal objects, like Stanley Cups, for the most part don’t pose these risks and can be microwaved in a pinch.

If you’re still not sold, check out this video of me risking my life by putting a dual-wall vacuum-insulated Yeti cup in my microwave. 

Watch until the end to see if there's an explosion. 

Avoid Microwaving Your Stanley Cup (If You Can Help It)

But just because microwaving your Stanley Cup won’t burn your house down, doesn’t necessarily mean you should do it.

Stanley’s official recommendation, after all, is to not microwave your Stanley Cup (or else). Just take a look at the bottom of your Stanley. 

And it’s probably for good reason. 

Microwaves work by using electromagnetic radiation, which passes through glass, ceramic, and paper containers, where it’s absorbed by the water content of your food or drink, creating heat.

The problem is, these waves are unable to pass through metal, meaning they’re deflected away erratically instead. 

This stops the beverage in your cup from getting warm but it can also make the stainless steel super hot.

At best this means your drink won't heat up very fast and, at worst, you could damage your microwave or compromise your Stanley’s vacuum seal or melt the exterior soft matte finish. 

Stanley Cups Are Too Tall For Most Microwaves Anyway

Even if you decide to take the plunge and microwave your Stanley Cup (please don't), chances are you won’t be able to anyway.

Compact microwaves have about 7 inches of vertical clearance and standard microwaves closer to 9 inches. 

Even with the lid and straw removed, the height of most Stanley Cups is still about 10 inches — meaning they won’t be able to stand upright unless you have a very large microwave regardless. 

Stanley cups aren't leak proof so lying them down isn't going to work. Plus when I put my Hydro Flask in the microwave lying down I did actually melt the lid:

If you need to reheat the beverage that is in your Stanley cup you'll first need to pour it into a microwave safe container, heat it up in the microwave then pour it back into your Stanley cup.