Before the Pour

In the information to use or lose box …

That morning cup of coffee. Almost makes you want to go back to bed just to wake up again for another first cup of the day. But wait, not every cup of coffee is equal. Brewed coffee varies in flavor and chemical make-up. Most of these changes are determined before you pour—from the bean, to roast, to grind and the brew method.

There are hundreds of chemicals in a cup of coffee. The major elements, including those with health impacts, are caffeine, chlorogenic acid, trionelline, kahweol and cafestrol. Don’t worry, no quiz today.

To a coffee tree, caffeine is an onboard insect repellent. To us humans, it enhances perception, reduces fatigue, improves alertness, may even help long term memory and boosts metabolic rate and energy expenditures. Current dietary guides suggest no more than 3 to 5 cups a day—the equivalent of 400 milligrams of caffeine.

Chlorogenic acid was mentioned recently in this blog so I’ll keep it brief. It’s the good stuff and lowers risk of cardiovascular disease and Type 2 diabetes.

Trigonelline is a bitter alkaloid that helps protect the brain from damage by blocking cancer cells, combating bacteria and lowering blood sugar and total cholesterol.

Kahweol and cafestol are diterpenes and make up the bitter taste of coffee and are found in the oil from the bean. They’ve been linked to preventing cancer cells from developing. Unfortunately also linked to raising serum levels of LDL cholesterol. If you make coffee with a paper filter or drink darker roasted coffee, the diterpene content is minimized.

On the bean side of the equation, there are around 68 types of Coffea that produce fruit (the beans are really the seed of the fruit). Two form the commercial foundation for coffee, arabica and robusto. Of the two, robusto has more caffeine. It makes sense, robusto is grown at lower elevations where insects thrive. Arabica is grown at higher elevations and contains more trigonelline and diterpenes.

During the roasting process sugars and fats degrade, amino acids and sugars combine to produce the wonderful flavors and aromas we’ve come to know and love. Medium roast beans contain more of the beneficial phenols and dark roast beans have slightly less caffeine.

Brewing coffee is a combination of time, temperature, pressure and turbulence. To over-simplify, grinding to expose the maximum surface area produces higher amounts of caffeine and flavor. Brewed for too long or at too high a pressure will over-extract very bitter taste elements. Brewed at too low a temperature will produce a weak, sometimes grassy taste.

Pick your brew method: Steeping (French press or pour-over), filtering (paper filter or other filter that traps sediment and oils), pressurization (espresso) or boiling (Turkish).  If you enjoy the creamy mouth-feel, avoid using the filtration method. It is the oils that create the crema consistency.

Information Sources:

The Coffee Bible

How to Science up your Coffee National Institutes of Health