Why Your Reheated Coffee Tastes Weird

Curious about why reheated coffee tastes off? Look no further! Our food scientist, Natalie Alibrandi, breaks down the scientific explanation behind this phenomenon and provides tips on how to prevent it.

Publisher: Well + Good

Full Article: The Scientific Reason Why Your Coffee Tastes Weird When You Reheat It in the Microwave (and How To Prevent It)

Date first published: April 22, 2022

Food and Beverage Journalist: Jordan Galloway

Image credits: Photo: Stocksy/Jeremy Pawlowski

Contributor at Nali Consulting: Natalie Alibrandi, Linkedin

Key contributions from Nali Consulting:

Forget spilling the tea. Today, we’re spilling the beans about a common coffee conundrum—why it tastes so bad when you reheat coffee in a microwave.

Unlike some foods and drinks that typically taste better after being zapped (like last night’s leftovers, a cold piece of pizza, or even a cup of mineral-rich bone broth), nuking your morning cup of joe tends to have the opposite effect, giving it a funny aftertaste that makes it downright undrinkable. Hardly the best part of waking up.

The reason for this, according to London-based food scientist Natalie Alibrandi, is simple. “Coffee naturally has volatile compounds, chlorogenic and quinic acid to name a few,” she says. “When you reheat your coffee in a microwave, you’re releasing more of these compounds that can taste astringent and bitter.”

And while this happens with all coffee—no matter how you brewed it—Alibrandi says there is one technique in particular that tends to make coffee tastes even worse when it’s reheated in a microwave. “If you make your coffee using a French press,” she says, “there will be more volatiles floating around that will continue to brew and become even more bitter.”

Okay, a bit of a buzzkill. But in an effort not to end on a sour note, we asked Alibrandi for her best practices when it comes to warming coffee back up so it tastes just as good the second time around.

How to reheat coffee without a microwave

Who hasn’t found themselves sitting down to their computer with a piping hot cup of coffee only to wind up getting lost in their inbox for so long that it’s lukewarm by the time you look up? Been there, done that. When this happens, “pouring your cup of coffee into a saucepan and reheating it slowly on the stovetop could be an option for less bitterness,” Alibrandi says. “But better yet, just brew a new batch.”

Depending on your workplace situation, these may not be feasible solutions, which is why Alibrandi recommends preventing your coffee from getting cold in the first place. “The best way to keep your coffee warm is to keep it in an insulated cup,” she says. “It will remain hot for about 30–45 minutes before it slowly starts to cool.” You can extend this window of time by investing in a mug warmer, and if none of those options are available, perhaps consider turning it into an iced coffee instead.