Sake factories are an essential part of both Japanese culture and the beverage industry producing a hugely popular traditional rice wine with a combination of rice, water, yeast, and koji mold. Sake brewing, which has a long history and recognized as a UNESCO Intangible Cultural Heritage of Humanity, is an industry that is harmonized with the natural world, dependent on the seasons and honouring both tradition and innovation. Water is a critical component in the sake brewing process, as it is used not only for the fermentation process but also for washing and steaming the rice. High-quality fresh water is vital, as it significantly influences the taste and quality of the final product. Most sake breweries are situated near pristine water sources, such as mountain springs or rivers as a result.
In 2024, Kobayashi Brewery renovated the former Kamikasuo Elementary School in Kamikasuo, a mountain village in Kanuma City, Tochigi Prefecture, and transformed it into Small Forest Brewing (Mae-Nikko Brewery), a sake brewery. Small Forest Brewing is surrounded by mountains and a crystal-clear river, and in harmony with this rich natural environment, the brewery produces locally brewed sake that is 'born in Kanuma and brewed in Kanuma'.
The consumption of fresh water in sake brewing can be significant, with large quantities used during rice preparation, fermentation and cleaning the brewery. Any water that does not end up in the product is needing treatment to remove any dissolved sugars, alcohol or nutrients that have become mixed together. Considering this, many sake factories adopt sustainable practices to manage their water usage efficiently. One of the ways that can have a large impact is embracing sustainable waste management practices such as using waste-to-energy technology, breweries can have an immediate reduction on their environmental footprint while preserving the beauty of the local environment for future generations.
Waste-to-Energy: Powering Our Vision
Using Watasumi’s process, water laden with byproducts from sake brewing is converted into renewable energy by bacteria. This waste-to-energy approach not only maximizes the energy within sugars etc naturally, but also significantly offsets CO2 emissions. Conventional wastewater treatment plants are energy-intensive, with energy use accounting for up to 80% of operational costs in some facilities, often powered by fossil fuels. By generating clean energy from waste, we reduce our reliance on fossil fuels which are normally consumed in the treatment process for air blowers, mixers and sludge removal, contributing to a meaningful decrease in greenhouse gas emissions. The energy is produced as renewable methane and direct electricity, which are used to power and heat Watasumi’s treatment plant.
Creating an Impact
In addition to generating renewable energy, our use of local resources and innovative technologies helps reduce the transportation footprint associated with raw material delivery and waste disposal. By sourcing locally and minimizing the need for long-distance transport, we further reduce CO2 emissions. This approach not only strengthens our connection with the community but also resonates with our global and European consumers who value sustainable and ethical production methods.
Sake production is relatively low in GHG emissions compared to other alcoholic beverages, largely because it relies on simpler ingredients and less energy intensive processes compared to some distilled spirits. However, for a small sake brewery wastewater can be a big source of GHG.
Wastewater that is untreated or poorly treated often undergoes anaerobic decomposition in lagoons or sewers, releasing methane, a greenhouse gas 25 times more potent than carbon dioxide (CO2) over 100 years. Advanced treatment methods like anaerobic digesters can capture methane for energy generation, and don’t require large amounts of aeration. A Watasumi treatment plant processing 1 cubic meters per day can avoid over 2000 kg of CO₂-equivalent (CO₂e) annually, which is about what 100 trees capture in a year.
We Don’t have Time
Investing in these strategies creates a win-win for climate action and sustainable development. Globally, adopting sustainable wastewater management could reduce emissions by 150-200 million metric tons of CO₂e per year. According to U.S. Environmental Protection Agency, this represents about 1-2% of the total GHG reduction needed to meet the Paris Agreement goals. By partnering with Kobayashi Brewery, we help ensure that every drop of water used in their sake brewing process is treated responsibly, preserving the purity of the environment and facilitating small companies working towards SDG. Our shared vision of sustainability and innovation demonstrates that traditional craftsmanship can coexist with modern environmental stewardship. Together, we are safeguarding natural resources and creating a legacy of sustainability for future generations.
We are looking for partners and talent to join Watasumi and help us on our mission, feel free to reach out.