The Best Ways To Reheat Coffee (Helpful Tips)

Last Updated on July 21, 2023 by Barry Gray

Don’t you hate it when you have the best cup of coffee in your hand, on your desk, traveling somewhere, and the coffee goes cold? Or, a miserable lukewarm? 

I know I do, and I hate wasting ‘that’ moment when I was kicked out of coffee heaven and into a stale coffee wilderness. 

That warm hug of caramel chocolaty goodness has gone, and in its place is a cold shower, more or less. I know I sound dramatic, but we are talking coffee here. 

The best drink on earth.

There are several ways to reheat coffee, from using the stovetop, to even the microwave if you are careful. So, cold coffee need not mean you have to throw it away, as there are ways to rescue it.

What can compete with the nutty grounding flavor of coffee that sometimes creates some of your best memories?

I keep a firm hand on my purse strings, and throwing coffee down the drain adds to this personal hurt. 

So, to counteract this, I have investigated the best warm-up techniques out there. 

how to reheat coffee

Using the Microwave

The first thing you want to know is, don’t microwave your cold coffee as you would anything else.

You might see a few tips advising you to do this, don’t, or do; life is all about choices. 

If you want to punch the delicious musky and warm fruitiness out of the brew you enjoy, use the microwave. It’s entirely up to you, but I wouldn’t without taking real care. 

It’s a fine line to use the microwave, and it’s all too easy for you to end up ruining an otherwise perfectly good coffee. 

reheat coffee in the microwave

How to Use the Microwave

The problem with a microwave is it destroys the flavor and aroma in an instant. Slow and steady is the key here to get your coffee lukewarm rather than piping hot.

I suggest using a medium heat and only hitting it for up to 30 seconds before checking. Anything more than this will ruin your coffee, so please avoid doing it.

Using a Stovetop

Keeping life simple is often the key to great success. Grab a pan and use the stove to reheat your coffee and I promise it will have a better outcome.

Once you have your pan, place it on super mild heat, anything warmer will knock any goodness out of your brew. Stir slowly. If you had foam on the coffee, you could save that simply by doing it this way. 

You should be looking at this taking around 7 minutes maximum, but keep an eye out for some steam appearing. That’s a sign your coffee is warm enough as you don’t want to overheat it in this instance.

But here’s something I think you need to think about, and that’s stopping your coffee getting too cold in the first place. 

They say prevention is better than cure, and I am all for that. 

I have learned to put my more expensive coffee in a thermos mug or flask. It makes a difference with how long it keeps heat in the coffee, so it stops me from stressing about how to warm it up.

So, if that sounds like a plan, here are some tips for choosing the best ones and remembering that your budget is often the starting point. 

What are the Best Cups and Flasks to Keep Coffee Warm

cups to keep coffee warm

You have a couple of options available when it comes to keeping coffee warm.

Vacuum Flasks 

If you love keeping your coffee piping hot, vacuum flasks will worm their way into your kitchen. 

But not all is equal in the land of thermos and flasks. 

A couple of years ago, I packed a picnic to impress my then-girlfriend, and I placed a flask of coffee in amongst the bree and cranberry, crackers, and fruit. 

That was more to sober us up from the champagne I had packed to add a bit of flair to the afternoon. My goal was twofold: propose to her and get her to enjoy the outdoors and walking. I can be a pretty romantic guy sometimes. 

All went well, including the proposal, as she is now my wife! But the coffee, not so much. 

It tasted strange and plastic-like; I tossed mine away. I admit it was a dampener for the whole afternoon, but then I am a perfectionist. She assured me that it tasted fine. 

Before you use flasks or insulated cups, here are some tips to avoid that plight. 

  • Use fresh, cold water. Using stale or warm water will make your coffee taste bland or even sour. So don’t grab the kettle and reboil the water in there. You can even use bottled water. Think ‘brand new.’ Each cup is a cup unto itself, even travel mug coffee. 
  • Grind your coffee beans fresh. Fresh coffee will taste better than pre-ground coffee.
  • Use the right amount of coffee. Too much coffee will make your coffee bitter, and too little coffee will make it weak. The pressure in flasks can make any beverage taste denser. 
  • Brew your coffee correctly. Follow your coffee maker’s instructions to ensure your coffee is brewed correctly.
  • Let your coffee cool down before adding it to the flask. If you add hot coffee to a flask, the heat will cause the plastic or metal to warp, giving your coffee a weird taste. It also encourages leaching. 
  • Clean your flask regularly. If you don’t clean your flask regularly, the residue can build up and give your coffee a weird taste. Use hot soapy water and a clean sponge, then rinse well. I have a special bottle washer to use with my flask. 

But I’m not finished with the tips to help you have a fantastic coffee without it going all weird.

  • Avoid using a flask with a plastic interior. The plastic can leach into the coffee and give it a weird taste. If you have read any other articles here, check out PVAs and the dangers of using plastic
  • If you’re using a stainless steel flask, ensure it’s well-insulated. This will help keep your coffee hot longer and prevent it from developing an odd taste.
  • If you’re using a glass flask, ensure it’s not cracked or chipped. This can also cause the coffee to develop a strange taste. All cups need regular checks for nicks and bumps. 
  • Only add milk or cream to your coffee once you drink it. Milk and cream can curdle if left in a hot flask for too long.

By following these tips, you can make coffee in a flask that will taste great and not have a peculiar taste.

How Do Flasks Work? 

They create a magical vacuum between the inner and outer walls of the flask, which locks in the heat and keeps your brew warm for hours. And if you’re worried about safety, choose one with a stainless steel inner to keep your sips safe and enjoyable. Nothing can beat a safe drink!

Consider bringing a flask for your daily hit when heading out for a hike or a walk. However, it’s essential to remember that if your flask is plastic-lined, it should be PVA-free. The cup insert should have the stamp of approval or not. 

Some flasks can make the coffee taste off. That’s my personal experience, and others keep the delicious flavor intact. Shop around and spend a little more money rather than bargain hunting. 

Spending more on a decent flask will save you money in the long term. See it as an investment. I’ve seen myself trying to penny-pinch, and I’ve landed up buying two, which cost the same price as a decent one.

 It will last a long time if you look after your flask, cup, or whatever you purchase. This principle goes for most things in life. 

If I use a flask while traveling to the office, I will dispense it into a cup when I arrive. Somehow this helps retain the flavor. 

Insulated Cups

insulated cup for coffee

These are handy, but I wouldn’t take an insulated coffee cup on a hike with me. It just gets in the way. I need both hands free. 

In this instance, I would go with the flask. 

Some backpacks have a slot to put your insulated cup into, so consider this option if you use the insulated mug. 

Insulated cups are a good option if you want something lighter than a vacuum flask. 

Insulated cups trap heat inside the cup. This keeps your coffee warm for a few hours, but not as long as a vacuum flask; I have had variations of one hour to around two hours before my coffee has become watery and lukewarm. 

The usual rule of thumb applies, spend more to get a better cup. 

Travel Mugs 

Travel mugs are designed to be taken on the go. They typically have a lid with a tight seal, which prevents spills and leaks.

 Many travel mugs are also insulated, which helps to keep your coffee warm for a few hours.

Some come with handles which I prefer, and others don’t. We all have our quirks! One fits perfectly in my cup holder in the car, so I use that for long drives. 

The drinking lip can be good or bad; experience with a few mugs might help you to decide which is best for you. 

When choosing a cup or flask to keep coffee warm, there are a few factors you’ll want to consider:

  • Size: How much coffee do you typically drink? If you only drink a small cup of coffee, you can get away with a smaller cup or flask. But if you drink a large cup of coffee, you’ll need something more significant.
  • Insulation: How long do you want your coffee to stay warm? If you need your coffee to keep warm for hours, you’ll need a well-insulated cup or flask. But if you only need your coffee to stay warm for a few minutes, you can get away with something less insulated. In other words, there is a price point difference. 
  • Portability: How portable do you need your cup or flask to be? If you carry it around, you’ll want something lightweight and easy to grip. If you have a backpack, see if it fits into the allocated space. 
  • Price: How much are you willing to spend? Vacuum flasks can be expensive, but insulated cups and travel mugs are more affordable.

Once you’ve considered these factors, you can choose the best cup or flask to keep your coffee warm. For example, I’ve seen myself purchase great coffee from an outlet and decanter it into my travel mug, which has worked out very well, but only if I use it quickly. 

My Conclusion

The best way to reheat coffee is on the stovetop. However, I suggest using flasks or mugs to keep it warm for as long as possible.

By trying to avoid allowing your coffee to cool as quickly, it stops you from stressing about heating it up and potentially destroying your cup. I feel that’s the best option, and it’s the one I recommend.