Japan — red shiso in umeboshi production: documented Heian period; yukari as a commercial product: Marumiya corporation (1970s); shiso cultivation in Japan: 8th century via Korean Peninsula import
Akajiso (赤紫蘇 — red perilla, Perilla frutescens var. crispa) and its applications represent one of Japan's most versatile and aromatic preservation ingredients. The bright magenta-purple leaves of red shiso are used primarily in two ways: as the colouring and flavouring agent in umeboshi production (the salt-fermentation of ume plums releases anthocyanin from the red shiso, turning the brine and plums their characteristic crimson) and as yukari (ゆかり) — dried, salted red shiso flakes used as a condiment sprinkled over rice. The yukari production process: fresh red shiso leaves are salted and massaged until they soften and release their liquid (extracting the bitter umeboshi-staining compounds in this first squeeze), then added to umeboshi brine, where they re-absorb the flavoured liquid and turn crimson. These crimson shiso leaves are then dried, crumbled, and salted to create yukari — an intensely fragrant, slightly sour and salty condiment. Green shiso (aojiso — or simply shiso in Tokyo dialect) is a separate variety used fresh as a garnish, in salads, and as a wrapper. The aromatic compound responsible for shiso's characteristic fragrance is perillaldehyde (perill-aldehyde), which also has antimicrobial properties — explaining its use as a garnish for raw fish (traditionally placed between sashimi pieces to inhibit bacterial transfer).
Intensely aromatic, slightly sour-savoury, herbal-minty-anise complexity — one of the most distinctive aromas in Japanese cooking; no substitute exists
{"Akajiso timing: red shiso is seasonal (July–August) — available only when the umeboshi production cycle calls for it; purchase at peak and process immediately","Bitterness extraction: the first salt squeeze and discard removes bitter compounds (acyloglucosinolates); second addition to umeboshi brine creates the crimson colour through acid reaction","Colour change chemistry: anthocyanins in red shiso turn from purple to bright crimson in the acidic umeboshi brine — a pH-dependent colour transformation","Yukari production: after umeboshi production, shiso leaves are dried in sun or oven at low temperature, then crumbled with salt — aromatic compounds are volatile, dry gently","Green shiso (aojiso): separate variety, used fresh — do not substitute for red shiso in umeboshi or yukari","Perillaldehyde antimicrobial: real food science basis for the traditional practice of placing shiso between sashimi pieces"}
{"Homemade yukari: add shiso leaves leftover from umeboshi production to a baking sheet, dry at 60°C for 2 hours, crumble with a pinch of salt — extraordinary aroma compared to commercial yukari","Fresh red shiso tempura: coat whole red shiso leaves in very thin tempura batter and fry briefly — the aromatics survive the brief frying and the result is beautiful","Shiso chiffonade as sashimi garnish: thinly sliced (chiffonade) green shiso is the canonical Japanese sashimi garnish — its antimicrobial and aromatic properties both serve the presentation","Shiso soy sauce: infuse a handful of fresh green shiso in premium soy sauce for 3 days — creates an extraordinarily aromatic condiment for tofu, cold noodles, or sashimi"}
{"Skipping the first salt squeeze — without removing the bitter compounds, the shiso imparts bitterness to the umeboshi and eventual yukari","Over-drying yukari at high heat — the delicate aromatic compounds evaporate; dry at 50–60°C maximum","Confusing red and green shiso — they are different varieties with different flavour profiles; not interchangeable in umeboshi production"}
Nancy Singleton Hachisu, Preserving the Japanese Way; Elizabeth Andoh, Washoku