Umeboshi is very sour pickle made from fermented plums. The plums are picked before they are ripe and dried for a couple days during the winter. Then they are heavily salted and packed in jars along with red perilla leafs for over a year.
During this time, the fermentation process produces plum vinegar and becomes very sour. The plum turns red, and very soft. They are typically dyed red using purple perilla herbs (called akajiso), or flavoured with katsuobushi, kombu or even sweetened with honey.
This Japanese style traditional condiment is believed to be a digestive aid, prevention of nausea, and for systemic toxicity, including hangovers. Green ume extract is used as a tonic in Japan. The citric acid is believed to act as an antibacterial, help to increase saliva production and assist in the digestion of rice.
Unlike other pickled Japanese vegetables, umeboshi does not have a strong smell, but a pleasant one. There are some umeboshi that have been pickled for over 50 years and they are prize for their complicated flavors.
Unfortunately, many umeboshi are not completely fermented these days. They are artificially flavored with salt and vinegar, and lack their true flavors.
There is a natural trend of favoring umeboshi that are not too sour and honey is often added in some products.
Umeboshi is high in citric acid and acts as a antibacterial agent. They were put in lunch boxes in Japan to prevent spoilage. It also acts as a digestive for patients with indigestion.
Umeboshi is finely chopped into a paste, and used in small amounts on some light fishes. They are also served as side dishes for rice or eaten on rice balls (often without removing the pit) for breakfast and lunch. They are occasionally served boiled or seasoned for dinner.
The fresh fragrance of the umeboshi matches fishes with delicate aromas. It is also rolled along with fresh perilla leaf to cleanse the palate and finish the night.