Here's everything that's hiding in your cup of coffee


book cover

Penguin Random House

This story comes from "This Is What You Just Put In Your Mouth?" by Patrick Di Justo.

This is what you just put in your mug: Cocaine-like brain chemicals and the juice of death.


This white powder is why the world produces more than sixteen billion pounds of coffee beans per year.

It's actually an alkaloid plant toxin (like nicotine and cocaine); plants use it to kill bugs. It stimulates us by blocking neuroreceptors for the sleep chemical adenosine.

When the sleep chemical is blocked by caffeine, the result is you, awake.

Hot H2O is a super solvent, leaching flavors and oils out of the coffee bean.


A good cup of joe is 98.75 percent water and 1.25 percent soluble plant matter.

Caffeine is a diuretic, so coffee newbies pee out the water quickly; java junkies build up resistance.

This substance creates a tarlike, medicinal odor in your morning wake-up.

Too much (in the range of one gram for every kilogram of body weight, far more than you'll get from a cup of coffee) makes rats stagger around their cages like the town drunk on New Year's Eve. It's also a component of cockroach alarm pheromones, chemical signals that warn the colony of danger.

Quinic Acid
That "sour coffee" burn in the pit of your stomach? This stuff. On the plus side, it's one of the starter chemicals in the formulation of flu-fighter Tamiflu.


3,5 Dicaffeoylquinic Acid
When scientists pretreat neurons with this acid in the lab, the cells are significantly (though not completely) protected from free-radical damage. Yup: coffee is a good source of antioxidants.

Dimethyl Disulfide
A natural product of roasting the green coffee bean, this compound is just at the threshold of detectability in brewed java. Good thing, too, as it's one of the compounds that gives human feces its odor.

That rich, buttery taste in your daily jolt comes in part from this flammable yellow liquid, which helps give real butter its flavor and is a component of artificial flavoring in microwave popcorn.

Ever wonder what makes spoiled meat so poisonous? Here you go. Ptomaines like putrescine are produced when E. coli bacteria in the meat break down amino acids. Naturally present in coffee beans, it smells, as you might guess from the name, like Satan's outhouse.

Chemically, it's a molecule of niacin with a methyl group attached. It breaks down into pyridines, which give coffee its sweet, earthy taste and also prevent the tooth-eating bacterium Streptococcus mutans from attaching to your teeth. Is there anything coffee can't do? It even fights the Cavity Creeps.


A.k.a. vitamin B3. Trigonelline is unstable above 160 degrees Fahrenheit; at that temperature, the methyl group detaches, unleashing the niacin into your cup. Two or three espressos can provide half your recommended daily allowance.

One of the many chemical cousins of caffeine, this mild stimulant and muscle relaxant is used to relieve the symptoms of asthma, bronchitis, and emphysema. The downside? It can react badly with some of the newer antibiotics.

Coffee addiction is the developed world's second-most prevalent back monkey (after nicotine). Songs have been written about it, from Johann Sebastian Bach's Coffee Cantata to Julian Smith's "Racist Coffee." Many people literally (the literal meaning of "literally") can't get through the day without it. It's no wonder why people really didn't like having coffee torn apart like this.

And it's also not surprising that few coffee producers offer the public any useful information about the chemicals in their brew. Nescafé and Starbucks, just to choose two examples at random, nearly completely gloss over the chemicals in coffee on their websites. Their PR people are even less helpful, limiting their replies to things like "the finest coffee beans" and "pure filtered water."

To get deep down inside the coffee bean, you have to search deep down in the Internet. On the USDA's website, there is a section called the Agricultural Research Service (ARS). And deep within the ARS website, there is a section called the Germplasm Resources Information Network (GRIN). And deep within GRIN, there is what looks for all the world like a rogue web page, containing something called Dr. Duke's Phytochemical and Ethnobotanical Databases.


Not a Doonesbury gag, this is a complete database taken from Dr. James Duke's groundbreaking work Handbook of Phytochemical Constituents of GRAS Herbs and Other Economic Plants. Duke found over a thousand chemicals in coffee alone. Anything you want to know about the naturally occurring plant-based chemicals on the USDA's "Generally Regarded as Safe" list can probably be found in Dr. Duke's. Happy hunting!

Reprinted from THIS IS WHAT YOU JUST PUT IN YOUR MOUTH? Copyright © 2015 by Patrick Di Justo. Published by Three Rivers Press, an imprint of the Crown Publishing Group, a division of Penguin Random House LLC.