Shiso

Shiso is the fresh aromatic leaf of Perilla frutescens, a purple-or-green mint-family annual native to the mountain slopes of East and Southeast Asia. The plant divides into two culinary lineages: ao-jiso, the flat green-leaf form used in Japanese cuisine; aka-jiso, the ruffled red-to-purple form whose anthocyanins dye umeboshi pickled plums their characteristic magenta; kkaennip, a broader, flatter and more mineral Korean cultivar wrapped around grilled meat; and tía tô, a bicoloured purple-and-green Vietnamese form layered into fresh spring rolls and bún chả. The aroma signature is the compound perillaldehyde, which accounts for fifty to sixty percent of the leaf's essential oil and delivers an odour profile that is instantly recognisable — anise, basil, cumin and citrus peel fused in a single inhalation — flanked by limonene, beta-caryophyllene and perilla ketone. The leaf is extremely perishable: picked in the morning it can be limp by evening and bitter within forty-eight hours, which is why it is almost always sold attached to its stem, refrigerated or shipped with cold packs, and why dried shiso is considered a different ingredient altogether. Kitchen uses are almost exclusively raw or barely warmed: tempura, sashimi garnish, ume-shiso maki roll, wrapped around grilled eel, chiffonaded into chilled noodles.