Why Does Reheated Coffee Taste So Bad?

crazy by Editorial Staff | Updated on August 7th, 2023

There’s a simple joy in a well-brewed cup of coffee — the rich aroma, the comforting warmth, the delicate flavors. However, the second it goes from piping hot to icy cold, the magic vanishes. You may have tried resurrecting it in a microwave, only to be assaulted with an awful, bitter taste. So, why does reheated coffee taste so terrible? Let’s dive in.

A New Age in Coffee Culture

Gone are the days when cafes had a pot of filter coffee brewing all afternoon. Today’s coffee culture revolves around artisan roasting houses, where every single bean is meticulously chosen and ground. This precise process involves crushing the beans using tiny hammers and pairing them with the perfect melted glacier water to bring out their flavor profiles.

bad coffee

When done right, the difference is evident. A well-prepared cup of coffee, with quality beans, can be delightful. Like a fine, vintage organic wine that you save for special occasions, there’s a certain allure to an expertly brewed cup of coffee. Of course, that’s not to suggest that an everyday table wine — or in this case, coffee — can’t be good.

The Curious Case of Cold Coffee

You might have noticed that coffee tastes fantastic when it’s hot and equally enjoyable when it’s cold (like iced coffee), but it becomes distasteful at room temperature. Some theories suggest that our taste buds are less sensitive to the bitterness of coffee when it’s hot or cold, but become more aware of it when the coffee is lukewarm.

Another significant factor is the aroma of the coffee. When it’s cold, the aroma isn’t as potent, and since our sense of taste is closely tied to our sense of smell, the flavor appears less appealing.

The Science of Reheated Coffee

As we reheat coffee, it induces more chemical reactions that result in a more pronounced bitterness. When coffee beans are roasted, heat causes the chlorogenic acid in them to degrade into quinic acid, an element that imparts a slightly acerbic and bitter flavor to coffee. While freshly brewed coffee balances these bitter elements with other delightful flavors, reheating causes an overproduction of quinic acid, which overpowers the other flavors and results in a bitter coffee. Factors such as the bean roast, the original beans’ quality, the time it sat before storage, its storage conditions, and brewing methods can all affect how your coffee tastes upon reheating.

The Downside of Warming Coffee Pots

Even coffee pots designed to keep your coffee warm throughout the day can make it taste bitter. These devices use heat, which leads to the same bitter flavor, just like reheating. That’s why, in general, it’s best to drink freshly brewed coffee within an hour of brewing for the best taste.

Different Roasts, Same Bitterness

Whether it’s a light, medium, or dark roast, reheating any type of coffee accentuates its bitterness, especially in dark roasts. They contain more quinic acid due to the high heat they’ve been subjected to during roasting.

Health Concerns about Microwaving Coffee

There are common misconceptions about microwaving coffee being potentially hazardous, but science disagrees. Microwaving food does not affect its fundamental structure or make it carcinogenic. All it does is agitate the molecules to heat up the substance. So while your coffee might taste terrible after microwaving, it won’t harm you.

Practical Solutions

If you’re tired of drinking cold coffee or dealing with its bitter reheated version, consider using an insulated cup or thermal flask. These containers can maintain your coffee’s temperature for longer. Alternatively, you can switch to iced coffee instead of warming it up. There are also various products like thermal mugs, smart mugs, or simple mugs with lids available today that can help keep your coffee warm.

The Art of Reheating

If you must reheat your coffee, there are a few things to keep in mind:

  1. Preheat the Container: This can help maintain the coffee’s temperature longer and prevent rapid cooling.
  2. Brew in Smaller Quantities: Instead of making a big batch, make smaller amounts that you can finish while they’re still hot.
  3. Microwave with Care: If you’re using a microwave to reheat, do it in short bursts to avoid overheating and further degradation of flavors.
  4. Monitor the Temperature: The ideal coffee temperature can be a source of contention among coffee enthusiasts, but it’s essential not to make it too hot to preserve its best flavors.

While reheating coffee is safe, you may find that the taste differs considerably from freshly brewed coffee. Also, dairy and sugar can spoil quickly, so be cautious when reheating coffee with creamer or sugar. However, with careful monitoring and proper techniques, you can still enjoy your reheated cup of Joe.

By understanding the science behind reheating coffee and the right ways to do it, you can find a method that provides you with a warm, enjoyable cup of coffee, anytime.

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Disclosure: No compensation or free products were received in exchange for writing this review.


Editorial Staff

The editorial staff at Crazy Coffee Crave is a team of coffee enthusiasts & Baristas who enjoy the one thing we all think about as soon as we get up in the morning. Trusted by thousands of readers worldwide.