By Harold McGee
Black pepper is the small dried berry of a climbing vine in the genus Piper, which includes a number of other spice and herb plants (see box). The berries of Piper nigrum form on a flower spike a few centimeters long, and take about six months to mature. As berries mature and ripen, their content of pungent piperine continuously increases, while their aromatics reach a peak and then decline. Fully ripe berries may contain less than half of the aroma that they had at the late green stage. The ripe berry skin is red, but turns dark brown to black after harvest thanks to the activity of browning enzymes. The inner seed is largely starch, with some oil, from 3–9% pungent piperine, and 2–3% volatile oil.