Fermenting miso in orbit reveals how space can affect a food’s taste

The space environment may impart a unique taste of space on foods fermented there. For miso, that led to a nuttier, more roasted flavor, according to a new study.

On the ISS, the Japanese condiment developed nuttier notes than earthbound versions.
Fermenting foods in space could provide a new culinary frontier.

When fermented aboard the International Space Station, the Japanese condiment miso tasted nuttier than two earthbound versions, researchers report April 2 in iScience. The finding not only reveals that fermentation is possible for a food orbiting Earth, it also characterizes a space environment’s influence on a food.
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Astronauts usually munch on freeze-dried foods void of most microbes, says industrial designer and researcher Maggie Coblentz of MIT’s Space Exploration Initiative. “Fermentation is a really exciting way to open that up, so to invite a diverse community of microbes that will interact with one another and also preserve food while growing and enhancing flavor.”

​A fermented food’s flavor can vary depending on the microbes and other elements of the surrounding environment. Miso was chosen for the experiment because of its firm structure, strong flavor and cultural significance, among other reasons. It represents the first known food deliberately fermented in space, says interdisciplinary food researcher Josh Evans of the Technical University of Denmark in Copenhagen.

Evans and colleagues combined cooked soybeans, salt and fermented rice called kōji to make about 1 kilogram of a miso-to-be mixture, keeping one-third of it. The rest went to Coblentz in Cambridge, Mass., who split her portion and sent one-third of the total mixture to launch into space from Florida in March 2020. All portions remained frozen until then. After 30 days of fermentation in each location, the batches were refrozen and later analyzed for microbial and chemical composition and flavor profile.

Fourteen tasters tried miso fermented in Copenhagen (left), the International Space Station (center) and Cambridge, Mass. (right). The space miso appears darker likely because of its elevated temperature aboard the ISS compared with the earthbound batches, which may have sped up the fermentation process. Maggie Coblentz

Fourteen tasters including chefs and researchers thought the space miso had nuttier and more roasted notes compared with the earthbound ones. These flavors are associated with compounds called pyrazines. The space miso contained more pyrazines, likely because the toastier temperature aboard the ISS sped up fermentation. (On average, the environment surrounding the space miso was roughly 36° Celsius — possibly due to heat-generating equipment nearby — compared with 23° C in Cambridge and 20° C in Copenhagen.)

All three misos bore similar microbes, although one bacterial species was found only in the ISS miso. Further, the fungus that fermented kōji showed more genetic mutations in the ISS miso than the Earth batches, possibly because of increased radiation exposure in space.
The researchers could not isolate the ISS miso’s fermentation variables, including radiation, temperature and microgravity, to attribute specific properties to them, Coblentz says. But all those environmental features — or the “space terroir” — contributed to the miso, imparting a unique taste of space.

This article first apeared on sciencenews.org. Questions or comments on this article? E-mail them at [email protected]