Tasty by John McQuaid Page B

cascade in the brain, which produces distaste. The outward result is a distinctive frown: mouth turned down, nose scrunched, tongue jutting out, as if to expel the unwanted substance. Faces across the animal kingdom, from lemmings to lemurs, display variations of this grimace.
    Yet humans have a love-hate relationship with bitterness that runs through all cuisine. The word “bitter” comes from the Indo-European root “bheid,” meaning “to split,” the same root as “bite.” In the Bible, bitterness is a metaphor for the suffering of the Jews. The bitter herbs used in the Passover seder, maror in Hebrew—horseradish, and parsley or endive dipped in salt water—recall the pain of bondage in Egypt.
    But bitterness tastes good (for those who tolerate it well) when combined with other flavors. If it disappeared, a spark would vanish from food. Broccoli and its relatives from the mustard family, including cauliflower, brussels sprouts, kale, and radishes, are the most cultivated vegetables on earth. In the South, collard greens are often braised with pork; the fat and rich flavors of the meat soften the bitter flavor of the greens, and the bitterness gives the smoothness a tang. Chocolatiers have spent the five hundred years since Hernán Cortés, the conqueror of the Aztec empire, brought cacao beans to Spain from Mexico tempering their natural bitterness with sugar and milk. An element of bitterness is essential to beer and pickles—and coffee.
    To make coffee taste good, the ancient, implacable force of bitterness is first summoned, then brought to heel. To understand how this process works, I visited the headquarters of Gimme! Coffee, a small chain of cafés and roasteries based in Ithaca, New York. The Gimme! roastery sits in a converted farmhouse on the edge of town. Inside, Jacob Landrau was monitoring two gas-fired Probat drum roasters, vintage black contraptions made from hand-cast steel parts. Each consists of a steel drum rotating inside a frame, like a clothes dryer, heated with gas jets to temperatures between 200 and 400 degrees Fahrenheit over the course of a roast, which takes about ten minutes. During the summer, temperatures can top 100degrees in the roasting room, which lacks climate ­controls—that’s a luxury reserved for the coffee beans, which are stored in an adjacent room where heat and humidity levels are kept constant.
    Raw, dried coffee beans are a pale green; they are seeds that have been removed from a reddish fruit, then soaked and cured. When chewed, they have a mealy consistency and a grassy taste that’s not particularly bitter. Many substances contribute to coffee’s bitter taste; the best-known is caffeine. But roasting itself is responsible for most of it, teasing out chlorogenic acid lactones, which break down to form phenylindanes as the beans turn dark brown in the final stages, making darker roasts more bitter.
    Landrau uses a laptop to track the temperature inside the roaster, but his own senses also guide him. If there’s too much heat, the beans desiccate; not enough, and they turn bitter too quickly. He follows the sound of the beans as they rattle around in the drum, their appearance, and their aroma, all of which change minute to minute. Each batch has its own character, based on the type and age of beans used, as well as subtle factors such as the atmospheric pressure, quirks in the roasters, and the time of day. All must be managed to trigger a particular set of chemical reactions that generate the perfect flavor. If there’s not enough bitterness, the coffee is lifeless; too much, and it’s undrinkable, like the day-old pot at the back of a 7-Eleven.
    On the day I visited, Landrau walked me through a roast from start to finish. After nine minutes in the roaster, the shells of the beans began to break, making a popping sound against the drum. This is called the first crack. Sometimes there are two or