Caffeine’s Dark Secrets

Stuff you might not know about C8 H10 N4 O2.

A patron enjoys a cup at Rojo's Roastery in Lambertville.
Photo by Erik Rank

Whether we drink regular or decaf, most of us give little thought to caffeine. Yet C8H10N4O2 is quite a remarkable, and not so little, molecule. Separated from the plants in which it naturally occurs, caffeine is an odorless, faintly bitter white powder. It’s a pharmacological cousin of another white powder, cocaine, but its stimulating effects are far less extreme, and in two to four hours the body rids itself of half the caffeine consumed. The rest subsides in 10 to 20 hours depending on many variables, including gender (women metabolize caffeine faster).

Caffeine, also known as 1,3,7-trimethylxanthine, occurs naturally in the green seeds of coffee plants. We call these seeds beans, and when roasted they turn brown. A common misconception, says Greg Lewis of Fair Mountain Coffee Company, is that the darker the roast, the more caffeine. “I can’t tell you how many times people come up to me and say, ‘I need a real dark coffee to wake me up in the morning,’” he says. In fact, roasting very slightly reduces caffeine content.

As for the two major species of bean, “Robusta,” says Coffee Afficionado’s Adam Bossie, “has about 30 percent more caffeine than Arabica, and tends to be heavier in body.” Geography is also a factor. “African coffees in general have more caffeine than, say, Central American and Indonesian coffees,” notes Lewis. “But it’s sporadic, and it jumps around from one country to another.”

The kick in your cup also depends on how the coffee is brewed. A 6-ounce cup of drip or French press contains from 120 to 150 mg of caffeine, Lewis says. Caffeine in espresso is highly concentrated (about 60 mg per ounce). Lewis attributes that to the high water pressure of espresso machines, the extra-fine grind used and that more grounds are packed into the holder ounce for ounce compared to drip.

Meanwhile, roasting styles have evolved. “The days of dark espressos are over,” Lewis says. Lighter roasts “show off the full range of flavors that may have been lost in a darker roast.”

Another misconception is that decaf is caffeine-free. According to Lewis, it generally retains about 2 mg of caffeine per 6-ounce cup.  Robusta beans may retain slightly more caffeine because they have more to begin with.

Most methods for removing caffeine use carbon dioxide or chemical solvents such as methylene chloride—sometimes used as a paint stripper. The federal Occupational Safety and Health Administration classifies methylene chloride as a “potential occupational carcinogen.”

Should decaf drinkers be concerned?

“There is no concrete evidence that chemicals used for decaffeination pose a health risk,” says Lewis. “Mainly because the process of roasting these beans after decaffeination burns off all the harmful solvents. For the end consumer, it’s okay.”

One company in Canada uses a water process for removing caffeine that it claims is “100 percent chemical-free.”

The Swiss Water Decaffeinated Coffee Company in Burnaby, British Columbia, sells beans decaffeinated using the trademarked Swiss Water method. They soak dry green beans in water until they swell to twice their size. The water is drained off and replaced with a solution called Green Coffee Extract, or GCE, which contains natural, water-soluble components of green coffee, such as amino acids, chlorogenic acids and sucrose. Through repeated soaks, the GCE basically sucks the caffeine out of the beans. After the GCE is drained off, the beans are dried.

David Kastle, the company’s vice president, says the dried beans are 99.9-percent caffeine free. Although it is not required, some roasters and retailers selling Swiss Water decaf affix the company’s logo to their products.

The public perception of caffeine, and of coffee itself, has changed dramatically over the years. “When I started in retail in 1986, people thought caffeine was bad,” says Oren Bloostein, owner of Oren’s Daily Roast in Jersey City. “The medical establishment advised zero caffeine for pregnant women. We carried a lot more decaf coffees than we do today.

“Over the past couple decades, coffee has been shown to provide protection against several forms of cancer, including endometrial cancer, as well as liver disease, and it helps avoid depression in the elderly. If you’re sensitive to caffeine and can’t sleep, that’s a problem. But caffeine is not going to cause any disease.”

The 2015 Dietary Guidelines Advisory Committee to the FDA recently issued a report stating that a healthy diet can safely include three to five 6-ounce servings of caffeinated or decaf coffee per day.

“Caffeine,” says Bloostein, summing up, “helps you get up in the morning, it helps with concentration and doing various tasks. Any previous association with diseases like pancreatic cancer were all shown to be false. There’s no question that coffee is beneficial.”

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