Brewing sake on the moon: A drink with...Soya Uetsuki
Decanter chats to Soya Uetsuki, who leads a 'Moon project' at Japanese sake brewery Dassai that recently proved its possible to produce alcohol in space.
On 27 February, a frozen capsule carrying the world’s first space-brewed sake returned to Earth, in a first-of-its kind experiment by Japanese sake brewery Dassai. The company seeks to understand whether sake can be brewed beyond Earth and, eventually, on the moon by the year 2050. A 100ml fraction of the liquid has already pre-sold for about $700,000 in a private auction, and the 200ml total is now being carefully thawed and analysed in Japan. Decanter spoke with Soya Uetsuki, project manager of the Dassai Moon roject.
‘This is the first time this has ever been done in history.
‘When humanity eventually settles on the moon, we want Dassai to be there to accompany people in their daily lives on the lunar surface as well.
‘The project began when our chairman and president [Hiroshi Sakurai], who had long dreamed of “one day brewing sake on the moon,” were approached by a space equipment manufacturer about conducting an experiment in space. Because of my background in life sciences, I was selected to lead the project.
‘I joined the company in 2021 after completing graduate school. Before joining the company, I conducted research on glaucoma at university. After joining, in addition to this project, I have also worked on research into the functionality of exosomes (extracellular vesicles) produced during the sake fermentation process.
‘Becoming the top researcher in the world is no easy task, but if I worked at the Dassai brewery, which is known for producing the best sake in Japan, I thought I might be able to help create the best sake in the world. That's why I decided to join the brewery as a kurabito (sake brewer).
‘Fermented foods such as miso, soy sauce, and vinegar form the foundation of Japanese food culture. This is not only because of their flavour, but also because of their functional and nutritional benefits. We believe fermented foods will also be essential for life on the moon.
‘I am responsible for designing the experiment to be conducted inside the ISS, while the actual brewing equipment was developed in collaboration with Mitsubishi Heavy Industries. Mitsubishi has decades of experience in the space development business, so they brought invaluable expertise to the project.
‘First and foremost, I don't know if you’re aware, alcohol is prohibited on the International Space Station. So, when we brought this proposal that we would ferment and produce alcohol on the ISS, NASA was like, “What’re you guys thinking?”
‘As you know, sake has been brewed in Japan for centuries. So, we were able to prove, not just anecdotally, but we gathered data and proved scientifically without a doubt that the actual production and brewing of sake is not dangerous.
‘We [sent] ingredients such as pre-steamed and dried rice (Yamada Nishiki) and dried koji mold from Earth to the ISS [on October 26, 2025]. These ingredients go into the equipment, and with the help of the astronauts, water [was] added to see if fermentation occurs.
‘The International Space Station, or ISS, is a completely confined space. If something goes wrong during an experiment, no one can go to help the astronauts. Sake brewing has a long history, but there's no data and knowledge about brewing in space. So we had to make a comprehensive list of all the byproducts generated during the fermentation process and submit data to show that each one of them met safety standards. Proving the safety of the experiment was our first major hurdle.’
'We were able to confirm alcohol was produced.'
‘The worst-case scenario would have been that fermentation does not progress in space, meaning sake cannot be brewed. However, this mission has ruled out that possibility.
‘The biggest difference on Earth is that yeast produces heat, and that heat then leads to convection. However, that’s really delayed and is slower in space. So, the moromi, which is the fermented mash, doesn’t mix very well, so everything progresses at a slower rate.
‘We have confirmed that under lunar gravity conditions, fermentation proceeds slightly more slowly compared to on Earth. We were able to confirm alcohol was produced.
'Our goal moving forward is to learn how to control this different behaviour from Earth and produce fine sake like the ones brewed on Earth … to prove that brewing sake under lunar gravity is technically feasible.’
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