of the tea and so can result in a "flat" brew. For these reasons, most tea masters will use a good clean local source of spring water. If this natural spring water is not available, bottled spring water will suffice. Yet high content mineral water also needs to be avoided. It is said that hard water needs to be filtered although the mineral content of even very hard water is solvated, and no amount of filtering will affect it. Temperature During the process of Gongfucha, the tea master will first determine the appropriate temperature for the tea being used, in order to extract the aroma of the tea. An optimal temperature must be reached and maintained. The water temperature depends on the type of tea used. Guidelines are as follows: for green tea ( typical) for white tea ( typical) for oolong tea ( typical) (boiling) for compressed teas, such as pu-erh tea The temperature of the water can be determined by timing, as well as the size and the sizzling sound made by the air bubbles in the kettle. At , the bubbles formed are known as "crab eyes" and are about in diameter. They are accompanied by loud, rapid sizzling sounds. At , the bubbles, which are now around in diameter and accompanied by less frequent sizzling sounds and a lower sizzling pitch, are dubbed "fish eyes". When the water is boiling, neither the formation of air bubbles nor sizzling sounds occurs. At high altitudes water boils at lower temperatures, so the above temperature ranges should be adjusted. Tools and equipment Below is a list of the main items used in a gongfu tea ceremony in Taiwan, known there as 老人茶 (Pinyin: Lǎorénchá). Brewing vessel, Yixing teapot, porcelain teapot, or a covered bowl gaiwan. Tea pitcher (chahai), or any matching size decanting vessel, used to ensure the consistency of the flavor of the tea (Chinese: 公道杯, Pinyin: gōng dào bēi). Hot water kettle, e.g. an electric kettle. Brewing tray, or a deep, flat bottom porcelain plate to hold spills (spills are typical). Tea towel or tea cloth, usually dark colored. Tea knife or tea pick for clearing the teapot spout and separating leaves from tea cakes. Tea cups (traditionally three cups are used in most instances), matching size. Also named Pinming Cup (). Timer. Strainer, a tea strainer () sometimes built into the tea pitchers. Tea holder, tea