Tsunan Sake Brewery Reports Progress on “Graphite from Sake Lees” Prototype

Tsunan Sake Brewery

07/21/2025 8:00 am

Tsunan Sake Brewery (Headquarters: Tsunan Town, Nakauonuma District, Niigata Prefecture; President: Kengo Suzuki) is pleased to report the successful prototyping of graphite derived from sake lees. This initiative was conducted in collaboration with Professor Yoshihisa Mori of Okayama University of Science and Space Seed Holdings Inc., as part of research and development on next-generation SPS* technology. For this effort, Tsunan Sake Brewery provided sake lees as the test material, leading to a successful trial that utilized an SPS device to sinter sake lees into graphite material.
* SPS (Spark Plasma Sintering) is an advanced material synthesis technology that enables fast, low-temperature sintering by applying electric current and pressure simultaneously to powdered materials. Compared to conventional methods, SPS allows for high-density materials with suppressed grain growth, making it particularly valuable for controlling nanostructures and creating metastable phases. Optimization of pressure, temperature, and current enables sintering of challenging materials and development of novel high-performance materials.

Background
At Tsunan Sake Brewery, we are actively engaged in our Sake Lees Upcycling Project, which aims to promote circular manufacturing and multi-layer utilization of regional resources by finding innovative uses for sake brewing byproducts, such as sake lees. This particular trial was conducted at Okayama University of Science to explore the potential of transforming sake lees—a microbe-derived biomass—into high-value carbon materials. The academic objective is to better understand how non-carbon components in sake lees affect material properties and conductivity. Industrially, the project aims to validate the feasibility of sustainable manufacturing utilizing microbe-derived raw materials.

Prototype Results
In this initial trial, sake lees were carbonized in an electric furnace, pulverized, and then sintered using a conventional SPS device. The process successfully produced a graphite sintered body with adequate hardness. Conductivity tests confirmed that sake lees-derived carbon resources hold potential for future applications.

Future Outlook
Tsunan Sake Brewery plans to continue this research alongside the progress of the next-generation SPS equipment being developed by Okayama University of Science and Space Seed Holdings, scheduled for advancement in FY2025. We aim to explore new material development under high-temperature and ultra-high-pressure conditions and investigate the feasibility of producing advanced carbon materials such as sake lees-derived carbon nanotubes, graphene, and diamond semiconductors.
Through close collaboration with research institutions, companies, and local governments, Tsunan Sake Brewery will continue to pioneer innovative applications of sake brewing byproducts such as sake lees. Our goal is to create circular innovations rooted in Japan’s primary industries.

About the Sake Lees Upcycling Project
The Sake Lees Upcycling Project is an initiative by Tsunan Sake Brewery that promotes circular manufacturing and multi-tier use of local resources through creative repurposing of byproducts such as sake lees. The project extends beyond conventional food applications to explore semiconductor materials and conductive materials derived from sake lees, research on sake-derived nanoparticles “SAKESOME,” and investigations into the use of sake brewing byproducts as raw materials for cultured food production. We seek to generate new value in diverse fields—including food, beauty, environment, and biotechnology—from the byproducts of our traditional sake brewing heritage.

About Tsunan Sake Brewery
Tsunan Sake Brewery is a sake producer headquartered in Tsunan Town, Nakauonuma District, Niigata Prefecture, Japan. Located in one of Japan’s heaviest snowfall regions, we use pristine natural meltwater from 2,000-meter-class mountains as brewing water. Our sake is crafted using carefully selected local rice varieties such as “Gohyakumangoku” and “Uonuma Koshihikari,” blending tradition and innovation in harmony with nature. Under our brand concept “Brew for Future — Brewing a Sustainable Future”, Tsunan Sake Brewery strives for excellence. In 2025, we were honored with the Niigata Governor’s Award (1st place) at the Echigo-ryu Sake Brewing Technology Championship.