Secrets to the Perfect Cup of Coffee
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America has a craving for the perfect cup of coffee. Though a steaming cup of joe has fueled the morning routines of many for generations, U.S. coffee consumption is now at an all-time high: Approximately 62 percent of us drink it every day—an increase of 5 percentage points over last year, according to the National Coffee Association.
Coffee drinkers across all age groups, from teens to seniors, have a seemingly insatiable thirst for the stuff. Many of us also have a growing preference for high-quality brew, with more than half the coffee we consume now classified as gourmet. It’s a preference that’s becoming much easier to indulge: The number of specialty coffee shops (think Intelligentsia, La Colombe Coffee Roasters, and Stumptown Coffee Roasters) increased tenfold between 1993 and 2013.
Powerful Health Benefits
A few decades ago coffee was considered not healthy and possibly harmful, says Edward Giovannucci, M.D., Ph.D., a researcher and professor of nutrition and epidemiology at Harvard’s T.H. Chan School of Public Health. “But more recent studies seem to suggest that there’s a benefit to drinking coffee,” he says.
The largest analysis we’ve seen examining coffee consumption and health, based on two studies that included more than 700,000 people from more than 10 countries, was published online in the Annals of Internal Medicine this past July.
Researchers from several universities across the U.S. and Europe found that coffee drinkers were less likely to die prematurely. In one study, those who drank one to three cups of coffee per day were 12 to 18 percent less likely to die during the study period from any cause, including cancer and heart, liver, and respiratory diseases. These results suggest that moderate coffee drinking is not detrimental to your health and could even have health benefits, says Neil Murphy, Ph.D., a scientist at the World Health Organization and a lead author of one of the studies.
Other research published in the past five years has found that regular coffee drinkers seem to have a lower risk of type 2 diabetes and Parkinson’s and Alzheimer’s diseases, as well as healthier livers, faster metabolism, and decreased risks of endometrial, prostatic, and colorectal cancers.
Studies have also confirmed what most of us already know: The caffeine in coffee can make you more alert and increase concentration, and may boost learning, decision-making, and performance on cognitive tasks.
Researchers think that the keys to coffee’s health benefits are the antioxidants and other biologically active compounds responsible for its distinctive flavor. “It could be a combination of all of these compounds working together,” says V. Wendy Setiawan, Ph.D., an associate professor of preventive medicine at the University of Southern California’s Keck School of Medicine and a researcher on one of the studies published online in July.
Some Coffee Caution
Increasing your coffee consumption beyond three cups a day might not up its health benefits. In fact, some studies have suggested a link between more than four or five cups a day and lower bone density, especially in those at higher risk of osteoporosis. (Caffeine potentially limits the body’s absorption of calcium, but adding 2 tablespoons of milk to each cup can help counteract this effect.)
Other researchers have found that certain compounds in coffee can raise cholesterol, although some evidence suggests that brewing with a filter might trap those compounds.
The caffeine in coffee can also have undesired effects: Just one cup can cause sleep problems and irritability in some people, and even regular coffee drinkers can experience headaches, nausea, anxiety, jitters, and increased blood pressure when they drink more than their bodies can handle.
How much caffeine is too much? U.S. government dietary guidelines say that up to 400 mg per day—the amount in about two to four 8-ounce cups of coffee, depending on the type of bean and how it’s brewed—can be part of a healthy diet for most adults.
Certain high-risk groups, however, should limit their caffeine intake. Pregnant women, for instance, should consume no more than 200 mg per day (the amount in about one 12-ounce cup of coffee), because caffeine could increase the risk of spontaneous abortion as well as growth delays in the fetus. Caffeine can also prevent the absorption of or create new side effects of common drugs such as certain antibiotics, antidepressants, and antipsychotics. Ask your doctor whether it’s safe to drink coffee if you’re on medication.
For people who need to avoid caffeine, drinking decaffeinated coffee may also be a healthy option, Giovannucci says. Recent research suggests that decaf provides similar health benefits to caffeinated coffee but without the side effects. Decaf has slightly fewer antioxidants than a regular cup, but research shows that it’s also associated with a lower risk of type 2 diabetes and many other perks.
—Additional reporting by Janet Lee
Battle of the Brews
We asked our expert tasters to evaluate coffee made using five popular methods. The results reveal that the flavor of the final product is shaped in part by the brewing technique you choose. (If you're reading this article on your smartphone, we recommend you rotate your phone to landscape mode to better view the tables below.)
Type | The Brewer | The Results |
Chemex For a clean, balanced cup | This hourglass-shaped pour-over coffee maker differs from other pour-over models because of the Chemex-branded filters, which are made of heavy paper and designed to regulate the filtration rate and keep sediment out. The glass body has a wooden handle that wraps around the neck of the carafe. It’s easy to pour coffee from the Chemex, but the narrow neck makes it difficult to clean by hand. The wooden handle isn’t dishwasher-safe, but it can be easily removed. | Coffee brewed in the Chemex earned high marks for complexity, acidity, and overall quality in our taste tests; the filter minimized the presence of solids in the cup. If you like an aromatic, balanced brew with sweet, juicy undertones, this one’s for you. |
French Press For a bold, full-bodied taste | French presses brew by allowing coarsely ground beans to steep (usually for about 4 minutes) in hot water. The grounds are separated from the coffee and pushed to the bottom of the carafe when a built-in filter is depressed. This sizable Bodum Chambord brews up to eight cups at once, and it’s easy to pour from. The fine-mesh filter forms a tight seal with the glass walls of the carafe, helping keep grounds out of the brewed coffee—a common problem with cheaper models. | Without a paper filter, this coffee holds on to its natural oils, creating a full-bodied taste. The mesh filter holds back most of the grounds, but small, powderlike coffee grounds (called “fines”) can remain in the brew, creating a somewhat viscous cup. |
AeroPress For a refined single serving | This one-of-a-kind miniature coffee maker sits on top of a mug and is small enough to travel with. Mix water and grounds in the carafe, then plunge the top down to force the brewed mixture through a micro filter designed to capture even very fine particles. Our tester noted that the process is a bit precarious because the tool has to be balanced on top of a cup. It’s also only big enough to brew a single cup at a time. | The AeroPress produced a high-quality brew, with good body and aromatics but just a touch less complexity. The company claims that—unlike a French press—this method leaves “no grit in your cup,” but our tasters found that the coffee sometimes contained a bit of fine coffee silt. |
Pour-Over For a simple, quality brew | Most pour-over coffee makers are little more than a filter basket that sits on top of a glass or ceramic carafe. The basket is lined with a paper filter, into which grounds are placed. This method puts you in control of a slow, careful pour over the entire bed of coffee, ensuring even distribution. The brewer is relatively easy to clean, dishwasher-safe—and cheap enough that you won’t be heartbroken if the carafe shatters in the sink: The filter basket will work on top of other containers as well. | This brewing method earned high marks. Our tasters found the pour-over coffee had full, juicy flavors that weren’t too aggressive, with a smooth feel and sweet taste. |
Drip For easy, no-nonsense joe | In general, drip coffee makers force you to sacrifice some control, but convenience often trumps perfection, especially first thing in the morning. At the top of our drip ratings, this programmable model brews in the ideal temperature zone of 195° to 205° F and prepares 40 ounces in just 10 minutes. The controls are generally easy to use and intuitive. | Scoring slightly lower than other methods in complexity, smoothness, and overall quality, the drip method is hard to beat on convenience. Our tasters noted a higher astringency, and the fruity, somewhat sweeter notes of the coffee were masked by a sharper acidity. |
Editor's Note: This article also appeared in the October 2017 issue of Consumer Reports magazine.
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