Japanese Umeboshi Plum Vinegar is not really vinegar but a pleasantly tart and salty juice extracted from making pickled Umeboshi plums. As it isn't fermented, it is suitable for those who are yeast intolerant and contains many of the healing qualities and nutrients associated with the pickled plums. Plum vinegar is produced during the pickling process from the liquid that rises after salt-soaked Japanese plums are pressed with stone weights. While it is not true vinegar and there is no acetic acid, the citric acid dissolved in the plum vinegar creates a strong, sour taste. It also contains a large amount of beneficial substances such as pectin and polyphenol.