Motivated by curiosity surrounding the food options available to astronauts and how microbial communities evolve in space, the researchers set forth to test whether food fermentation was possible in space and, if so, how foods fermented up there would taste compared to their counterparts made on Earth.

The ingredients spent 30 days fermenting in the space station before returning to Earth to be compared with two batches of miso made at the same time back on terra firma. Analysis found that the ISS miso fermented successfully, but that there were notable differences in the bacterial communities present, and that the ISS fermented condiment had a more roasted, nutty flavour than the Earth miso while still maintaining the classic salty umami flavour that we know and love.