Brix very similarly to sucrose with respect to specific gravity as a function of concentration, or compounds which are present in small amounts (minerals, hop acids in wort, tannins, acids in must). In any case, even if °Bx are not representative of the exact amount of sugar in a must or fruit juice they can be used for comparison of relative sugar content. As specific gravity was the basis for the Balling, Brix and Plato tables, dissolved sugar content was originally estimated by measurement of specific gravity using a hydrometer or pycnometer. In modern times, hydrometers are still widely used, but
Wine in China "materia medica" compiled in the late Han, states that grapes could be used to produce wine. In the Three Kingdoms era (220–280 AD), Wei emperor Cao Pi noted that grape wine "is sweeter than the wine made [from cereals] using ferments and sprouted grain. One recovers from it more easily when one has taken too much." Grapes continued to be grown in the following centuries, notably in the northwestern region of Gansu, but were not used to produce wine on a large scale. Wine thus remained an exotic product known by few people. Not until the Tang dynasty (618–907) did