Usuke Asai (麻井宇介, 1930–2002)

Life

Usuke Asai (麻井宇介) was born in 1930 and joined Mercian after wartime service and university studies. He trained extensively in Bordeaux during the 1960s and 1970s, returning to Japan with both technical knowledge and a wider European framework for thinking about wine. Within Mercian he rose to become chief winemaker at the Katsunuma site, with responsibility for Koshu and Muscat Bailey A.

The Sur Lie Breakthrough

By the late 1970s, Koshu had a serious image problem. The variety produced thin, sometimes oxidative, often dilute wines. Tastings against international whites were embarrassing. Asai had observed in Bordeaux and the Loire how lees-contact aging could add body and texture without adding oak — the Muscadet sur lie tradition in particular. In 1983 he applied the technique to Koshu at Mercian Katsunuma.

The result was transformative. Koshu fermented in stainless steel and held on its fine lees for three to six months gained mid-palate density, a faint reductive aromatic, and a savory-umami quality that conventional Koshu had never had. The wine that resulted — Mercian "Koshu Sur Lie" — became the prototype for the modern Koshu category. Within a decade, every serious Yamanashi producer had adopted some version of the technique.

Writing

Asai wrote prolifically in Japanese on winemaking philosophy, Koshu, and the relationship between European technique and Japanese identity. His best-known book, 『ワインを学ぶ人に』 ("For the Person Studying Wine," various editions), became the standard introductory text in Japanese sommelier programs for two decades. His more technical writing on lees aging and indigenous varieties shaped how the next generation of Japanese winemakers thought about their craft.

Death and Legacy

Asai died in 2002. His students — directly through Mercian and indirectly through his writing — include essentially every senior Japanese winemaker now over fifty. The sur lie technique he introduced is so universal it is no longer associated with him by name; it is simply how serious Koshu is made.

His role in Japanese wine is best summarized as: Kawakami created the grapes, Asai created the modern style.

Details

• Born: 1930
• Died: 2002
• Role: Chief winemaker, Mercian Katsunuma
• Key innovation: Sur lie aging applied to Koshu, 1983
• Major writing: 『ワインを学ぶ人に』 and other Japanese-language standards