Koshu

Koshu — literally "old sake" — is Japanese rice wine (nihonshu) that has been deliberately matured for years, sometimes decades, until it deepens from pale straw into amber and gold and takes on a rich, sherry-like, nutty character quite unlike the fresh, fragrant sake most drinkers know. It is not a way of brewing but a way of aging: an ordinary junmai or honjozo is cellared — cool in tank or bottle, or warm at ambient temperature — long enough for slow oxidation and Maillard-type browning reactions to build up dried-fruit, caramel, toffee, soy and roasted-nut aromas and a deep, savoury, faintly bitter concentration. At roughly 15 to 18 percent alcohol it runs from off-dry to distinctly rich, with a viscous, honeyed weight and a long, umami-drenched finish. Long overshadowed by the industry's cult of freshness, koshu is a small but revered category — Japan's answer to aged sherry, tawny port or an old madeira — prized as a slow-sipping digestif and a partner for strong, savoury and rich food.