Speaker 1: Welcome to brain Stuff production of I Heart Radio. Hi
Speaker 1: brain Stuff, I'm Lauren vogel Bomb and this this is
Speaker 1: a classic episode from our archives. In this one, we
Speaker 1: explore a question that's near and dear to my heart
Speaker 1: because I love the taste of coffee. So why does
Speaker 1: microwaved coffee taste so bad? Hey, brain Stuff, Lauren volke
Speaker 1: Bomb Here. Hot coffee is supposed to be hot. Cold
Speaker 1: coffee is supposed to be cold, and that's the deal.
Speaker 1: It's pretty simple. The problem, then, with hot coffee is
Speaker 1: that you can't drink the whole cup while it's at
Speaker 1: the optimal temperature unless you're willing to really guzzle it.
Speaker 1: So when it gets cold, you've got a few choices.
Speaker 1: Drink it cold, reheat it, or just pour that cup
Speaker 1: down the drain and start over with a fresh pot.
Speaker 1: All three of these approaches are either perfectly fine or
Speaker 1: completely barbaric, depending on whom you ask to Some hot
Speaker 1: coffee that's gone cold is revolting to others. The reheating
Speaker 1: process renders it completely undrinkable, but that doesn't stop us
Speaker 1: from occasionally popping a cup of nine hour old office
Speaker 1: Joe into the microwave at four pm to power through
Speaker 1: until bedtime out of some combination of desperation and mild masochism.
Speaker 1: Research into why reheating this humble drink is pretty much
Speaker 1: non existent, but it most likely has to do with
Speaker 1: our sense of smell. Humans aren't great at separating our
Speaker 1: gusta tory that's taste and olfactory that smell responses, and
Speaker 1: coffee has aromas and flavors that hit all five of
Speaker 1: the tastes that can be picked up by your tongue
Speaker 1: and other mouth and nasal passage nerves sweet, salty, bitter, sour,
Speaker 1: and savory. So your personal sense of smell has a
Speaker 1: lot to do with how coffee tastes to you, whatever
Speaker 1: it's temperature, and however that temperature was achieved. That's because
Speaker 1: the chemical makeup of coffee is astoundingly complex. Even though
Speaker 1: its reputation relies heavily on the presence of caffeean coffee
Speaker 1: gets its flavor from around a thousand different chemical compounds. Also,
Speaker 1: the final flavor of the coffee you enjoyed this morning
Speaker 1: was the product of a dizzy ng array of variables,
Speaker 1: including the temperature and weather conditions the beans grew under.
Speaker 1: When the beans were harvested, how they were dried, stored,
Speaker 1: and roasted, and how they were ground and brewed. So
Speaker 1: while the compound three methyl buttinol might make your cup
Speaker 1: of joe taste a little caramel like and ethyl no no,
Speaker 1: it may give it some fruity or notes. Each step
Speaker 1: of the process either brings out or suppresses any one
Speaker 1: of these aromatic compounds differently, which brings us to reheating.
Speaker 1: We spoke with Christopher Hendon, a postdoctoral fellow at the
Speaker 1: Chemistry Department at m I T and author of Water
Speaker 1: for Coffee, a book about how coffee interacts with water.
Speaker 1: He said reheating coffee in principle can be an absolutely
Speaker 1: fine approach to achieving a tasty beverage. In practice, this
Speaker 1: is not usually observed because people reheat in ways to
Speaker 1: promote the loss of delicious volatile compounds, and so the
Speaker 1: process of heating, cooling, and heating again drives smelling and
Speaker 1: tasty compounds out of the cup. According to Hendon, coffee
Speaker 1: experts seem to prefer a drink that has been brewed
Speaker 1: within the previous five to twenty minutes. It turns out
Speaker 1: most people prefer the coffee as it cools to around
Speaker 1: a hundred and fifty degrees fahrenheit that's sixty five degrees celsius.
Speaker 1: This has to do with the way our taste pathways
Speaker 1: respond to temperature in our food. But when we put
Speaker 1: something in our mouth that's too hot or too cold,
Speaker 1: we can't detect all of the compounds that contribute to
Speaker 1: its flavor. Since coffee has loads of these compounds, the
Speaker 1: temperature of the drink can affect the taste. Brewing the
Speaker 1: coffee brings out certain aromatic compounds, but whether the cooling
Speaker 1: process changes the chemistry seems to be controversial. Hendon says
Speaker 1: it is absolutely benign, while others claim it makes the
Speaker 1: drink more acidic as the coffee is exposed to air
Speaker 1: and oxidizes. Reheating coffee to the same temperature it was
Speaker 1: when it was first brewed might help you reach that
Speaker 1: sweet spot temperature wise, but it also has the potential
Speaker 1: to cause additional chemical reactions that further alter the flavor.
Speaker 1: And if you're reheating coffee that already has milk or
Speaker 1: sugar in it, that's even more in the way of flavors, proteins, chemicals,
Speaker 1: and compounds to contend with. So although many coffee connoisseurs
Speaker 1: will tell you it's a lost cause once your coffee
Speaker 1: goes cold. Others say it's just important to reheat your
Speaker 1: coffee as slowly as you can in order to prevent
Speaker 1: additional chemical reactions. But if you're reheating in the microwave,
Speaker 1: don't worry about ghosts of past foods heated in that
Speaker 1: microwave coming back to haunt your coffee. Hand And said,
Speaker 1: the concentration of the volatile chemical composition of say, splattered
Speaker 1: pasta sauce, is pretty low, so I would be surprised
Speaker 1: if we could attribute the bad taste of microwaved coffee
Speaker 1: to only that. Our advice crank your microwaves power down
Speaker 1: to or lower and sap your cup of coffee in
Speaker 1: thirty second intervals to prevent does faster. But of course
Speaker 1: we encourage you to run your own experiments. Today's episode
Speaker 1: is based on the article hand Signs Explain why microwave
Speaker 1: coffee tastes so terrible on how stoffworks dot com, written
Speaker 1: by Despolin Shields. Brain Stuff is production of I Heart
Speaker 1: Radio and partnership with how stuff works dot Com, and
Speaker 1: it's produced by Tyler Clang. Before more podcast It's my
Speaker 1: heart Radio, Visit the I heart Radio app, Apple podcasts,
Speaker 1: or wherever you listen to your favorite shows.