Of the five basic tastes, I find bitterness to be the most interesting—not only from an ingredient perspective but also looking at our behavior in response. In most recipes, we usually try to avoid tasting bitterness, and, as cooks, we’ve developed various ways in the kitchen to make the taste more palatable by trying to reduce it, cover it up, or remove it entirely.
There are, however, some bitter foods that we’ve learned to like, such as alcohol, tea, cocoa, and, of course, coffee, one of the most popular bitter beverages in the world. There’s a common theme throughout these four ingredients: They’re stimulants. We appreciate the bitter taste in these foods because the stimulant activity—working on our brain and nervous system to make us more alert—acts as a reward. Our brains learn that drinking a cup of coffee provides positive reinforcement in the form of its stimulant activity.