Brewing is the extraction into water of desirable substances from the coffee bean, in amounts that produce a balanced, pleasing drink. These substances include many aroma and taste compounds, as well as browning pigments that provide color (almost a third of the total extract) and cell-wall carbohydrates that provide body (also almost a third). The flavor, color, and body of the finished drink are determined by how much ground coffee is used for a given volume of water, and by what proportion of that coffee is extracted into the water. Inadequate extraction and a watery, acid brew are caused by grinding the beans too coarsely, so that flavor is left inside the particles, by too brief a contact time between coffee and water, or by too low a brewing temperature. Overextraction and a harsh, bitter brew result from an excessively fine grind, or long contact time, or high brewing temperature.