Fermenting Miso in Space Gives It a Unique Flavor, Study Finds

Yahoo

08-04-2025

There's something about the space environment that changes the flavor of miso in interesting and subtle ways.
An experiment to create the fermented soybean paste simultaneously here on Earth and aboard the International Space Station found that the space miso tasted intriguingly nuttier and more roasted than miso produced at the same time in the US and Denmark.
"Fermentation [on the ISS] illustrates how a living system at the microbial scale can thrive through the diversity of its microbial community, emphasizing the potential for life to exist in space," says industrial design scientist Maggie Coblentz of the Massachusetts Institute of Technology.
"While the ISS is often seen as a sterile environment, our research shows that microbes and non-human life have agency in space, raising significant bioethical questions about removing plants and microbes from their home planet and introducing them to extraterrestrial environments."
Miso is a tasty, salty fermented paste used extensively in Japanese cuisine. It's made from steamed soybeans, salt, grains such as rice or barley, and kōji (Aspergillus oryzae), the fungus behind the miso fermentation process.
The team's experimental setup was pretty simple. The researchers prepared three batches of miso starter, then sent these batches to the three different locations: Cambridge, Massachusetts; Copenhagen; and low-Earth orbit aboard the International Space Station.
In the higher-radiation and microgravity environment of the ISS, the experimental batch fermented for 30 days, housed inside a specially designed sensing box that monitored temperature, humidity, pressure, light, and radiation.
Meanwhile, the Cambridge batch was housed in an identical box, but the Copenhagen batch was not. This allowed the Copenhagen batch to serve as a control to gauge whether the sensing box itself altered the fermentation process.
Once the 30-day fermentation process was complete, the miso was shuttled back home to Earth to be analyzed and compared to the two terrestrial control batches.
That analysis involved genome sequencing to study the microbe populations in the miso pastes, assessment of the physical properties such as texture and color, and an evaluation of the flavor profiles.
The space miso fermented successfully, but it was noticeably different from the Earth miso pastes.
The microbial communities in the space miso, for example, contained higher populations of Staphylococcus epidermidis and Staphylococcus warneri, possibly as a result of the warmer temperature on the space station. In addition, the bacterium Bacillus velezensis was only identified in the space miso.
As for the flavor of the three miso pastes, all had similar aroma compounds and amino acids, and the characteristic yummy salty flavor expected. However, the space miso was nuttier and more roasted in taste, the researchers found.
This flavor is associated with pyrazine compounds that probably emerged as a result of the higher ISS temperatures too, which would have accelerated the fermentation process.
It's a fascinating result that demonstrates the differences environmental tweaks can make on how life organizes itself, and how we might eat as we explore the stars – especially since our sense of taste is dulled in microgravity.
"By bringing together microbiology, flavor chemistry, sensory science, and larger social and cultural considerations, our study opens up new directions to explore how life changes when it travels to new environments like space," says food scientist Joshua Evans of the Technical University of Denmark.
"It could enhance astronaut well-being and performance, especially on future long-term space missions. More broadly, it could invite new forms of culinary expression, expanding and diversifying culinary and cultural representation in space exploration as the field grows."
The research has been published in iScience.
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