A mere five-degree difference in temperature will affect the crystallization. Ten years ago, when instruments for heating were not as accurate as they are today, Sun Chao had to rely on his own eyesight to determine the approximate temperature.
由於鋅結晶的生成過程極敏感，十年前標示窯火溫度的儀器又不夠精確，冬夏可差達六十度，孫超只好「土法煉釉」﹘﹘用自己的眼睛觀察火舌顏色的變化，來判斷溫度。