How to reheat coffee

Picture of smoking hot coffee

In the U.S., approximately 517 million cups of coffee are consumed each day. Similarly, 98 million cups of coffee are reportedly enjoyed daily in the UK. Being one of the most popular and sought-after beverages, it’s estimated that 2 billion people drink coffee each day all over the globe.

If you’re a coffee lover, there’s nothing worse than stumbling upon a hot coffee that’s gone cold. Maybe there was more left in the carafe and you forgot about it, or perhaps you’re a busy mom who set her coffee down somewhere and forgot about it until lunchtime. Better yet, perhaps you made too much the day before and put the leftovers in the refrigerator. However you stumble upon this issue, there are right ways to correct it and wrong ways that shouldn’t be attempted. In this article, we will explore the proper ways to reheat a cup of coffee, as well as some potentially sticky situations you can find yourself in when trying to reinvigorate your “cup of joe.”

Reheating Is Possible

Even though your leftover or forgotten coffee has gone cold, it is salvageable. In fact, if reheated properly, it can taste fresh and delicious in no time. Before jumping into the process, however, you should first understand which coffees can be reheated and which are not good candidates.

Reheating Candidates

Black coffee is the only safe contender for this job. Heating up coffee that has dairy or non-dairy additives is susceptible to curdling. It can also cause the coffee to burn more easily during the reheating process.

Unless it has been refrigerated, the coffee being heated up should be no more than 4 hours old. After 30 minutes, the flavor of the coffee will be compromised and start to diminish. Once it gets to the 4-hour mark, however, the oils in the coffee start to go bad and the brew will become more acidic and distasteful.

Reheating with a Stove

Once you have determined that your cold coffee is black and only sat for a few hours at the most, the next step is to heat it back up. The best method for this is on the stove. This is mainly because you can control the temperature, and the key to this process is going slow and keeping the temperature low.

When using this method, it’s suggested to use a thermometer to know when the coffee has been sufficiently heated up without jeopardizing the flavor. Although everyone is different and has their own preferences, it is suggested that coffee should be between 155°F and 175°F.

Steps to Take

For this process, you will need a pot, a stove, and a mug to drink out of. For precision, you should also have a thermometer to gauge how hot the coffee is getting. If it gets too hot, the coffee could burn. This would leave the coffee with an unappealing taste.

  1. Put the coffee into a pot.
  2. Place the pot onto the stove and turn the heat to medium-low.
  3. Check the coffee with your thermometer. Once it reaches the desired temperature (somewhere close to 155°F), remove the coffee from the stove.
  4. Carefully pour the coffee into the mug. From here, you can either drink it black or add your favorite extras.

Reheating with a Microwave

Using this method to heat up coffee, although it is doable, is not preferred. This is mainly because you have little control over the temperature and the process happens quickly. Reheating coffee in the microwave is delicate and can often leave the coffee tasting burned, stale, and bitter. It does work, however, if you are in a pinch.

Steps to Take

For this process, you will need a microwave, a microwave-safe mug, a thermometer, and leftover coffee. You will also want to make sure that the microwave’s power setting is set to medium, not high. For the best results, you will need to actively watch and tend to the coffee during this process.

  1. Fill the microwave-safe mug with cold coffee.
  2. Place the mug in the microwave and set it for one minute. After one minute, remove the mug, stir the coffee, and check the temperature. If the temperature is not high enough, place the mug back into the microwave and run it for another 30 seconds.
  3. Repeat this process in 30-second increments, followed by checking the temperature with a thermometer, to make sure the coffee reaches the correct temperature (approximately 155°F).

Reheating Don’ts

It’s not recommended to reheat coffee in a coffee maker. For one, the appliance is not made for reheating coffee. Even if you had some old coffee in the carafe and you turned on the machine, the hot plate wouldn’t get the coffee back up to drinking temperature. Secondly, the coffee sitting on a hot plate can also lead to the coffee tasting burnt and disgusting.

Caffeine, Aroma, & Taste

While the caffeine content in a cup of coffee will not be affected when reheated, the taste and aroma could be. Reheating coffee is a safe method to bring your morning cup of coffee back to life. This process, however, alters the chemical compounds in the coffee and results in a change of flavor and aroma. This is especially true when using a microwave, as the heating process happens very quickly.

Wrap It Up

Reheating your coffee, although it might alter the taste or aroma slightly, is perfectly safe and easy to do. If you are in a time crunch, a microwave will work. If you have the time, however, heating coffee up on the stove with a thermometer is the preferred method.

If you are thinking of reheating a cup of coffee, make sure that it hasn’t been sitting out on the counter for more than 4 hours. If it’s older than that, the oils in the coffee start to go bad. Also, coffee that has already been mixed with dairy or non-dairy creamer should not be reheated, as it is susceptible to curdling and scalding. If you are thinking of reheating your cup of coffee today, make sure it’s black and relatively fresh before you get started.