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Can You Reheat Coffee in a Microwave? All the Facts.

We’ve all had that moment where we make a hot drink, get sidetracked and next thing we know it is stone cold! Instead of wasting a cup of coffee we wonder whether it is possible to reheat your coffee in a microwave?

Reheating your coffee is fine but expect your coffee to lose its original taste. The microwave breaks down the aromas which are the key element for giving coffee its flavours so the salt, bitter, sweet, and sour tastes that you taste in your cup.

How long do you heat up coffee in the microwave?

Coffee beans and mug next to a microwave.

I don’t like wasting food in general, so I sometimes microwave my coffee even though there are loses of aromas and tastes.

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To reheat half a cup of coffee it will take about 45 seconds. Of course, this is dependent on your microwave so if you don’t find it’s hot after 45 seconds keep reheating for intervals of 10 seconds until it’s at the temperature you desire.

Can you microwave old coffee?

Yes, as long as it is safe to do so. Having milk in your coffee does add extra risk depending on how long you’ve left your coffee out for and the temperature in the area. If the temperature is low then generally it will be fine but in a country like Australia during a hot day the milk could be unsafe to drink if left out for a couple of hours.

The other thing to consider is that coffee has two milestones, the first is at the 30-minute mark when the coffee starts to cool and lose flavour. The second stage is around four hours, where the coffee starts to become more acidic and the oils go bad.

Does microwaving coffee remove caffeine?

Even though you lose the aromas in the coffee the caffeine does not evaporate or otherwise disappear after brewing. No matter how long you leave your cup of coffee for there still be as much caffeine in your coffee after a couple of hours as there is just after a fresh brew.

Best Way to Reheat Coffee

Taste is an important part of coffee so if you do want to reheat that cup of coffee the best way to reheat your coffee is by heating it up on the stove top at a low temperature. That way you get to keep all those aromas and tastes you love.

Simply grab a pan out of your kitchen, any will do, then on a low-temperature heat the coffee. Stir with a spoon until it is at the desired temperature.

Don’t rush the process as you could end up burning the coffee and end up making it taste worse! If you are in a rush the microwave would be your best route.

Other Products That Keep Your Coffee Warm

Always that person that lets their coffee get cold? There are products out there today that keep your coffee at right drinking temperature.

Mug with a Lid

coffee cup with a lid to keep coffee warm and bag of coffee beans

A simple way to keep your coffee warm is to have a mug with a lid on it. Something like a reusable mug will keep your coffee nice a toasty for a little longer. This won’t keep your coffee as warm as a thermal mug but an extra 30 minutes is better than nothing.

I currently have an Ecoffee Cup which is made out of bamboo with a silicone lid that has a capacity of 12oz. I love that it saves on landfill as well and all around environmentally friendly whilst making my coffee last for that bit longer.

Thermal Mugs

Thermal mugs have been around for years and are the perfect way to keep your coffee warm. Plus they are great travel mugs for those morning commutes!

When searching for the right thermal mug to keep your coffee warm the features you should look for is an auto-seal lockable lid and easy to clean. Depending on how long you wish to keep your coffee warm then this will change your choices as well. For keeping drinks warm for longer look for a double-wall vacuum-insulated option, preferably constructed in stainless steel.

Stainless steel will cost more when purchasing but if heat retention is a priority this type of thermal mug is for you.

According to most manufacturers, drinks will stay hot for four or more hours.

Smart Mug

A higher priced option in the mug market is the smart mugs. The manufactures of these mugs boast that their products are able to keep your beverage at your desired temperature for long periods of time.

Using the Ember smart mug as an example it’s expected when using the mug on the go with a set temperature that the mug will last for 2 hours on battery. A few factors will affect the battery life like the pour temperature, ambient temperature, and desired temperature.

The smart mugs connect to your phone via an app on your phone (or Apple Watch). This will allow you to control the temperature and track your caffeine consumption. An LED on the side will warn you if the drink is too hot.

Smart mugs are generally not dishwasher safe and require handwashing after use.

In conclusion, it’s fine to reheat your coffee in the microwave if you are happy to lose the flavours and just want the caffeine. If coffee flavour is important to you then look at reheating your coffee on the stove or purchasing a mug that will keep your coffee warmer for longer.

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Ed Lozon

Tuesday 1st of December 2020

I have heard, that when you heat your coffee over a period of time, it loses not only its flavor, but the caffeine drops as well. Is this true?


Wednesday 2nd of December 2020

I've not heard that the caffeine disappears, it should have the same level as when you brewed it. The flavour will drop if you leave your coffee for too long.

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