Brewing the Perfect Cup of Joe

There were many shaky hands at a regional coffee competition in Santa Cruz one weekend in early March, though it was hard to tell if the tremors were due to nerves or just the free-flowing coffee at the tasting bar.

Baristas from Colorado to Hawaii competed to earn a trip to the national championship in April. Brewer’s Cup participants, mostly from California, brewed a mystery coffee, tweaking their favorite brewing method to bring out the best flavors of that coffee. Winners from the first round used their own beans to brew in the finals.

As the brewing finalists’ recipes show, making the perfect cup of coffee is not as simple as adding hot water to ground coffee beans. The grind size, water temperature and brewing method can change the flavor. And coffee connoisseurs delight in controlling every detail.

Even Starbucks, an oft-maligned giant of corporate coffee, is experimenting with brewing methods. They’ve just opened a
brewing “laboratory” in Amsterdam.

We describe an ideal cup of coffee in terms of its strength, aroma, flavor, acidity, and finish. Coffee enthusiasts quantify those descriptions as the concentration of coffee compounds in the final brew and the amount of flavor extracted from the beans.

There are 2000 different flavor and aroma compounds in roasted coffee beans. About 30% of those flavors dissolve in hot water, and only some of those are palatable. A cup of coffee brewed to full extraction is bitter and undrinkable. So brewers aim to pull the sweet and complex flavors from the grinds before the beans leach their bitter compounds.

Reaching that extraction sweet spot depends on several factors, including the ratio of water weight to bean weight. The size of coffee grounds and the brew time matter too. If your coffee is weak, grinding the beans finer increases the surface area of the grounds exposed to the hot water and thus increases the amount of flavors extracted. But watch the clock once the hot water hits the grounds. Brew any pot too long and those bitter flavors seep out from the beans.

Water temperature is another way to control the flavor of coffee. Water warmed to 192-203 degrees Fahrenheit is best, says Lalo Perez-Varona, an independent coffee researcher from San Francisco.

Coffee associations around the world recommend numerical standards that describe the perfect cup of coffee in terms of the percentage of extracted flavors, but ultimately individual taste preferences determine what is an excellent cup of coffee.

For a tasty cup of joe, pick beans with flavors that you like, use your favorite brewing method, and troubleshoot using this chart, changing one factor at a time.

But how do you choose a brewing method? Sure, your choice influences the flavor of the coffee. Completely immersing the coffee in hot water, as in a French press, tend to brew coffee with more sweetness and body, says Perez-Varona. Paper filters trap some of the oils and solids, clarifying the flavors in the coffee.

Brewing with a siphon, also called a vacuum pot, gives you excellent temperature control due to the consistent heat source underneath the pot. This process is beautiful to watch:

Intelligensia Siphon

But for me, that choice reveals something about a person’s personality. Peter Molignano, of Fortnight Coffee Company in Los Angeles, brought his handmade wooden siphon holders to the competition in Santa Cruz. He warmed the upper part of the siphon halogen lightbulbs mounted in a matching wooden box.

From the ritual of brewing to precision analysis, a cup of coffee is a union of science and art. Because my morning routine doesn’t leave time for experimenting with water temperature, brew time, grind size, and water and bean amounts, I’ll leave the science – and the art -- to the experts at my favorite local coffee shop.