Why food made in space tastes different

By Stephen Beech

Food made in space tastes different, according to new research.

The traditional Japanese condiment miso had a nuttier flavor when made on board the International Space Station (ISS), say scientists.

Miso is traditionally created by fermenting cooked soybeans and salt.

When scientists successfully made some miso on the ISS, they found that it smelled and tasted similar to miso fermented on Earth - but with a slightly nuttier, more roasted flavor.

The team hopes that their findings, published in the journal iScience, will help broaden the culinary options available to astronauts, improving the quality of life during future long-term space travel.

Study co-lead author Dr. Joshua Evans, of the Technical University of Denmark, said: “There are some features of the space environment in low earth orbit - in particular microgravity and increased radiation - that could have impacts on how microbes grow and metabolize and thus how fermentation works.

“We wanted to explore the effects of these conditions.”

Motivated by curiosity surrounding the food options available to astronauts and how microbial communities evolve in space, the researchers set out to test whether food fermentation was possible in space.

And, if so, how foods fermented in space would taste compared to their counterparts on Earth.

The research team sent a small container of “miso-to-be” to the ISS in March 2020, where it stayed for 30 days to ferment before returning to Earth as miso.

Two other miso batches were fermented on Earth: one in Cambridge, Massachusetts, and the other in Copenhagen, Denmark.

Environmental sensing boxes kept tabs on the fermentation environment, closely monitoring temperature, humidity, pressure, and radiation.

Once the ISS miso was back on Earth, the team analyzed its microbial communities, flavor compounds, and sensory properties.

They found that the ISS miso fermented successfully, but that there were notable differences in the bacterial communities present in the misos.

Study co-lead author Maggie Coblentz, of the Massachusetts Institute of Technology (MIT), said: “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.

“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.”

The researchers also compared the flavor and scent of the ISS miso with that of the Earth miso.

They found that the samples mostly contained the same aroma compounds and similar amino acid profiles.

The researchers who tasted the misos reported that all the samples tasted good, with similar salty umami flavor profiles that were recognizable as miso.

However, they noted that the ISS miso had more of a roasted, nutty flavor than the Earth miso.

Dr. Evans said: “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.

“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.”

Coblentz foresees the impact of the research extending far beyond a single jar of miso made in space.

She said: “We’ve used something as fundamental as food as a starting point to spark conversations about social structures in space and the value of domestic roles within scientific and engineering fields.

“The way we design systems in space sends a powerful message about who belongs there, who is invited, and how those people will experience space."