Umeboshi (梅干し, “dried ume”) are Japanese salted ume – a fruit, Prunus mume, usually called a plum but closer to an apricot. Firm early-summer ume are packed in salt and weighted until they sit in their own sour brine (umezu), often colored deep red with red shiso leaves, then dried in the summer sun for a few days. The result is intensely salty and sour, eaten in small amounts with rice – most famously in the middle of an onigiri.
Salted More Than Fermented
Umeboshi are often filed under fermented foods, but at 15–20% salt few microbes can grow; the sourness comes mainly from the fruit’s own acids, drawn out into the brine. They aren’t a probiotic food. What the long salting does change is the fruit’s chemistry:
- Raw ume are not safe to eat. Unripe ume contain high levels of cyanogenic compounds (from amygdalin) and aren’t fit to eat as they are; processing them into umeboshi, umeshu or salted ume breaks these compounds down substantially, according to Japan’s Ministry of Agriculture (MAFF). Don’t taste the fruit before it’s salted, and keep raw ume away from children.
- Red shiso adds more than color. In a 2024 study, ume pickled with red shiso had 13 times more phenolic compounds than ume pickled with salt alone, with rosmarinic acid forming during pickling (Suwannachot & Ogawa, 2024).
How Salty Are Umeboshi?
Very. Japan’s official food composition tables list traditional salt-pickled umeboshi at 18.2 g salt (7,200 mg sodium) per 100 g, and the milder “seasoned” type, usually sweetened, at 7.6 g salt (3,000 mg sodium) per 100 g (MEXT; MEXT). One traditional umeboshi of about 10 g therefore has roughly 1.8 g of salt – close to a third of the WHO’s 5 g daily limit. Eat them as a seasoning, not a snack, especially if you watch your blood pressure.
What About the Health Claims?
Ume have a long reputation in Japan for upset stomachs and fatigue. The research is limited:
- H. pylori: in an observational study of 1,358 Japanese adults, eating more ume wasn’t linked to lower infection rates, though among infected volunteers the high-intake group had less stomach inflammation (Enomoto et al., 2010). In a pilot of 18 infected people who drank an ume juice concentrate twice daily for 12 weeks, the infection wasn’t cleared (Nakajima et al., 2006). Ume isn’t a treatment.
- “Alkalizing”: food doesn’t change the pH of your blood, which the body keeps in a narrow range regardless of diet.
Where Umeboshi Come From
The best-known growing area is around Minabe and Tanabe in Wakayama Prefecture, where ume orchards on poor, stony slopes are kept alongside coppice forests that also provide a habitat for honeybees. FAO designated the Minabe-Tanabe Ume System a Globally Important Agricultural Heritage System in 2015 (FAO GIAHS).
Japan’s other salt- and bran-based pickles include nukazuke and sake-lees kasuzuke; for a salty seasoning with live koji enzymes, see shio koji, and for miso, our homemade miso guide.