A coffee bean is a seed of the Coffea plant and the source for coffee. It is the pip inside the red or purple fruit often referred to as a cherry. Just like ordinary cherries, the coffee fruit is also a so-called stone fruit. The fruits; cherries or berries, most commonly contain two stones with their flat sides together. A small percentage of cherries contain a single seed, instead of the usual two. This is called a “peaberry”. The peaberry occurs only between 10% and 15% of the time, and it is a fairly common (yet scientifically unproven) belief that they have more flavour than normal coffee beans. Like Brazil nuts (a seed) and white rice, coffee beans consist mostly of endosperm. The two most economically important varieties of coffee plant are the Arabica and the Robusta; ~60% of the coffee produced worldwide is Arabica and ~40% is Robusta. Arabica beans consist of 0.8–1.4% caffeine and Robusta beans consist of 1.7–4.0% caffeine. In addition to caffeine, there are other active ingredients in coffee.One of these substances is ethyl phenol. This substance makes you refreshed by drinking coffee in the morning.Quinic acid is one of the most important acids in coffee ingredients. It gives coffee a sour taste. This acid also increases the acidity as the temperature of the coffee cup decreases. Caffeic acid is another ingredient in coffee. This acid mostly causes bitter tastes in coffee. This acid has many antioxidant properties that its presence in coffee is very useful for humans.Other acids in coffee ingredients are decaffeic acids. These acids protect the brain against free radical molecules that cause strokes and are essentially one of the most important antioxidants in coffee.Brazil, Vietnam, Colombia, Indonesia, Ethiopia and Honduras are the largest coffee producers.