Why Reheated Coffee Tastes So Bad, And What To Do Instead

A cup of coffee has a predetermined lifecycle: You pour a steamy mug of joe, set it down next to your laptop to refrain from burning your tongue, and before you know it, an hour has passed and your coffee is stone cold. You pop it in the microwave to nuke it for a few seconds, press the cup to your lips and grimace. It’s bitter. Bitter in a way that makes you wonder if someone poured a Romeo and Juliet-style vial of poison into it.

Does this sound familiar? No matter how you’re trying to reheat your coffee ― in the microwave, on the stovetop, whatever ― you’ve no doubt shared this experience. Because however you do it, reheating coffee brings out compounds that make it taste decisively more bitter. We talked to experts who explained how this happens and offer a few realistic solutions to help you avoid falling into this pattern.

Now that you’re working at home more than ever, read up and never drink another bad cup of reheated coffee.

Why reheating coffee makes it taste bitter

Emily Rosenberg, director of education and training operations at Stumptown Coffee, explained to HuffPost that before your coffee beans are even roasted, their DNA is made up of acids and compounds that are just waiting to turn bitter when they’re heated up.

Green (unroasted) coffee contains chlorogenic acids, and the roasting process breaks those down into quinic acid (whose flavor you can associate with quinine in tonic water) and caffeic acid. While chlorogenic acid has a bitter taste, quinic acid and caffeic acid both have an even more pronounced bitter, astringent flavor.

“All coffee has some amount of bitterness,” Rosenberg said. “But in freshly brewed coffee, there is also plenty of sweetness and acidity that balance the bitterness and