Ume juice is extracted by preserving the fruits in sugar. In China, sour plum juice (Chinese: 酸梅汤; pinyin: suānméitāng) is made from smoked ume (Chinese: 乌梅; pinyin: wūméi; literally "dark plum"). It ranges from light pinkish orange to purplish black in color and often has a smoky and slightly salty taste. It is traditionally flavoured with sweet osmanthus flowers, and is enjoyed chilled, usually in summer. The juice produced in Japan and Korea, made from green ume, tastes sweet and tangy, and is considered a refreshing drink, also often enjoyed in the summer.
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In Korea, maesil juice, which is marketed as a healthful tonic, is enjoying increasing popularity. It is commercially available in glass jars in sweetened, concentrated syrup form; it is reconstituted by stirring a small amount of syrup into a glass of water. The syrup may also be prepared at home by storing one part fresh maesil in a container with one part sugar (but no water).-(Wikepedia)