Astronauts Brought Miso Into Orbit on the ISS — Here’s What They Discovered

Astronauts aboard the International Space Station (ISS) do a lot of important work to help advance science, including experiments and research to support humanity’s potential future as outer space explorers. And that extends to researching how to make food taste better on both long-haul space missions and down here on Earth. 

In April, researchers published the findings of their study titled “Food Fermentation in Space” in the open access journal iScience, highlighting the differences in taste between miso fermented on Earth — specifically in Cambridge, Massachusetts and Copenhagen, Denmark — versus miso fermented in the ISS.

If you’re unfamiliar with miso, this fermented soybean paste is a powerhouse of flavor. It’s a staple in Japanese cooking, and the umami-packed paste can be used for everything from classic miso soup to marinades, salad dressings, and so much more. There are many different varieties of miso and variables that can influence its flavor. But one factor that hadn’t been tested until now? Space.

For the first stage of this experiment, the scientists made three batches of miso starter and sent it off to the three locations. The misos on board the ISS and in Cambridge were each placed inside an environmental sensing box to carefully monitor variables like temperature, humidity, and radiation levels. The one in Copenhagen was left in a standard container to act as a control group to see if it was the box or space that made changes to the miso. 

After a 30-day wait, the miso onboard the ISS was sent back to Earth for analysis against the two already on terra firma, where scientists could measure its texture, color, microbial population, and flavor profiles. 

The researchers found that the miso fermented in space had higher levels of certain microbes — microscopic organisms that are crucial to the fermentation process — which they note could be because of the warmer temperatures aboard the ISS. 

“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,” Maggie Coblentz, an industrial design scientist at the Massachusetts Institute of Technology, explains in a statement. 

The flavor of the three miso pastes also differed. The researchers found that the space miso exhibited a darker color along with a “nutty” and “roasted” taste, which could be attributed to an increased production of pyrazines — an organic compound that the report says displays “baked, roasted, and nutty flavor characteristics” — in the space miso due to the higher temperatures.  

“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,” Joshua Evans, a food scientist at the Technical University of Denmark, details.

What does this mean for the future? According to Evans, these learnings “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.”