Dassai 23 Centrifuge (1.8 L)

When a competitor reached 24% seimaibuai, Hiroshi Sakurai extended Dassai's polishing run a final 24 hours — arriving at 23% and triggering 168 continuous hours of milling that removes 77% of each Yamada Nishiki grain before a single drop of water touches the rice. That competitive act of precision effectively reset the ceiling for ultra-polished Junmai Daiginjo globally. The brewery sits deep in the mountain valley of Shuto-cho, Iwakuni City, Yamaguchi Prefecture, where the regional water classification Seiryu — clear-stream soft water — is purified further on-site; low mineral content in soft water suppresses harsh fermentation byproducts and amplifies the delicate ester profile that extreme polishing makes possible. Rice is washed in 10 kg units in running water and soaked approximately 15 minutes, with water absorption rates monitored by competing parallel brewing teams who adjust fermentation temperature variables batch by batch — a data-driven artisan model that replaces the traditional seasonal toji. Dassai was the first sake brewery in Japan to deploy a centrifuge commercially (c. 2000), separating sake from mash without mechanical pressure to preserve the most volatile top-note aromatics that conventional pressing would shear away. Freshness is locked in via the patented Hayata low-temperature bottling and hot-water-shower pasteurization method (Patent 2013-008455, commercialized 2016), immediately rapid-cooled post-treatment. The 1.8 L magnum format slows oxidative ingress relative to bottle surface area, extending the serving window for table-side pouring.