Can You Reheat Coffee In A Microwave? (The Correct Way To Do It)

Last Updated on October 20, 2021 by John Moretti

It’s one of those insanely busy days at work, and you felt that you couldn’t go another minute without a steaming cup of coffee. You let it stand for a while and finish up what you were busy with. Finally, the moment has arrived for you to savor this much-anticipated cup of goodness, except… it’s cold. Will reheating it in the microwave be a good idea? 

You can reheat coffee in the microwave, but you should do it at a lower power level to avoid burning the coffee. Reheating coffee in the microwave is safe. The reheating process will change the chemical makeup of the coffee and alter its natural flavor and aroma. 

There are other ways to reheat coffee, for example, on the stovetop. But realistically, who has time for that? The microwave is a quick and easy tool that can warm up a cup of coffee within a matter of seconds. So, can all types of brews be reheated, and how many times is it safe? Read on to find out. 

What Happens To The Coffee When You Microwave It? 

microwave coffee

A cup of coffee contains an astounding amount of chemicals, including phenolic compounds, antioxidants, and aromatic compounds. The complex composition of these constituents gives your cup of coffee its flavorsome taste and a pleasant aroma. 

When you brew the coffee, the heat makes the grounds release their flavor and give off that heavenly coffee aroma. The sweetness and acidity are perfectly balanced, giving you a satisfying cup of freshly brewed coffee. 

Once the coffee has cooled, the taste can almost become flat and bland. When you then decide to pop your cup of coffee in the microwave, other chemical changes occur that may be detrimental to the flavor of your coffee. 

Microwaving coffee at high power (until it’s technically too hot) will give it a bitter taste, and the smell won’t be nearly as satisfying as with a freshly brewed cup of coffee. This happens because reheating coffee releases too much of the caffeic acid and quinic acid, contributing to an overly bitter, acidic flavor. 

Microwaved coffee doesn’t have to mean ruined coffee. When you microwave it the right way, you can still have an enjoyable cup of coffee that you won’t have to put to waste. 

How To Reheat Coffee In The Microwave – The Right Way

set microwave to reheat coffee

If you’re like me and don’t have the time to stand in front of the stove to reheat your coffee, then using the microwave is the best and quickest alternative.

The trick is to heat your coffee slowly and gradually (as you would on the stove). You don’t want to microwave your coffee at full power because this increases the chance of burning the coffee and will leave you with bitter-tasting coffee. 

Before reheating your coffee, turn down the microwave’s power intensity to two levels below the default setting. For example, if your microwave is set at 10 (full power), you should turn it down to 8. The length of time you should microwave it depends on how much coffee was left in your mug and how cold it was. 

Usually, half a cup of cold coffee takes only between 30 to 45 seconds to heat up to a good drinking temperature. If it’s not there yet after 45 seconds, then continue reheating it in 30-second intervals until it’s at your desired temperature. 

Although your coffee may still not taste as great as when it was freshly brewed, using this method to reheat it in the microwave lowers the risk of having to drink bitter coffee. 

Is Reheating Coffee Detrimental To Your Health?

Reheated your cup of coffee in the microwave won’t hold any dangers for your health. There have been myths that microwaves have a carcinogenic effect, but this is not true. No amount of reheating your coffee in the microwave will give you cancer. 

Microwaved coffee still has the same amount of caffeine as when it was still fresh in the pot. Caffeine is very stable and won’t diminish in the reheating process. So if you’re afraid you won’t be getting in your normal dose of caffeine, rest assured, you will. 

Reheating coffee in the microwave won’t put your health at risk, but it does slightly lower the health benefits of the coffee. The antioxidants in coffee, called chlorogenic acids, start breaking down at lower temperatures. So leaving your coffee to go cold will reduce the number of antioxidants you get in with your cup. 

Although changes to your coffee do occur after you microwave it, none of these changes will lead to health issues.  

Important: Always make sure the cup you’re using is microwave-safe! 

Can You Reheat Coffee Containing Milk And Sugar?

microwave latte

You can reheat coffee that contains milk (or creamer) and sugar, but you need to take extra care when doing this. The reason for this is because milk and creamer may scald or curdle when you reheat it at high temperatures. Always do it at medium or low intensity and in shorter intervals to avoid this type of disaster. 

How Many Times Can You Microwave Coffee? 

There’s no set rule stating how many times you can microwave your coffee. Just keep in mind that your coffee will become more and more bitter every time you reheat it. 

Although it won’t damage your health, I don’t think sticking a cup of coffee that has already been brewed to perfection back into the microwave over and over is worth it. If it’s about to be the 10th time you need to head back to the microwave with cup in hand, perhaps it will be better just to brew a new cup or skip the coffee altogether. 

Is It OK To Reheat Coffee The Next Day? 

If you drink your coffee black, nothing is stopping you from reheating it the next day. However, don’t expect it to taste the same. In addition to losing flavor, cooled coffee may turn rancid due to the oils in the coffee going bad. A day-old cup of coffee won’t ever match up to an aromatic, freshly brewed cup. 

There is a catch if you like to add some milk and sugar to your coffee. You cannot keep dairy out of the refrigerator for too long. The milk in your coffee won’t last well if it’s been left abandoned on your desk for hours (or days). Unless you want to be drinking sour milk, I recommend that you toss the coffee away and opt for a fresh cup with fresh milk.  


You don’t have to give up on your cold cup of coffee and end up pouring it down the drain. I know the chances are high that today won’t be the first or the last time you have to decide whether you want to reheat your cup of coffee or make a fresh one. 

If it’s a busy day and you really need a warm drink before your next meeting, you can rely on the microwave to turn your forgotten, cold cup of coffee into a steaming cuppa joe in an instant!