Constituting 98 to 99 percent of the finished brew, the water must be neutral in flavor, at the proper temperature, and in the right volume. The optimal water for coffee brewing is free of any unpleasant flavors or aromas. The Specialty Coffee Association of America recommends that the water have a purity of 50 to100 ppm total dissolved solids, no iron, and no taste, odor, and particulates, with a pH of 6.5 to 7.5. Temperature plays a strong role in the creating of specialty coffee. Heat the water to 197 to 204 degrees Fahrenheit (92 to 96 degrees Centigrade), and extract all the appealing flavors and aromatics of the coffee. Cool water will not allow enough flavor and aromatics to be extracted, while water too hot will burn the grounds and produce a flat, bitter brew. Volume is critical in controlling the coffee-to-water ratio; for drip brewers the ratio is 64 ounces of water to between 3.25 and 4.25 ounces of freshly ground fine-grind coffee, as directed for Gold Cup Standard (see below*) brewed coffee. This ratio, water temperature, and purity will allow the extraction of 18 to 22 percent of the soluble material from the coffee, yielding a brewed coffee concentration of total dissolved solids (flavoring materials) at 1,150 TDS to 1,350 TDS.