Miso in Space: 5 Things We Learned from the NASA Fermentation Experiment

Space Terroir is real—and miso might just be the secret to feeding our future selves. Where no soup has gone before.

A bowl of miso soup floats in orbit. This image was AI-generated, but the curiosity behind it is real. If miso can ferment in space, we can handle an AI visual on Earth.

When researchers launched a batch of miso into orbit aboard the International Space Station (ISS) in March 2020, they weren’t just sending food into space. They were testing the boundaries of fermentation, microbial adaptation, and maybe even taste itself. Here are five things we learned from this cosmic culinary experiment:

1. Fermentation Doesn’t Need Gravity — Just Guts (and Koji).

Turns out, miso can ferment just fine in zero gravity. A blend of soybeans, rice koji, and salt was sent to the ISS for 30 days and came back fully fermented. Microbes don’t care about your earthly physics—they just want to do their job.

2. Space Miso Tastes Toastier.

The ISS averaged warmer temperatures than Earth-based controls, which led to higher levels of pyrazines in the miso—compounds that deliver that nutty, roasted flavor. Think of it as interstellar umami, slow cooked by cosmic radiation and insulation.

3. The Microbes Mutated — but Not into Aliens.

Aspergillus oryzae, the hero mold in miso fermentation, showed more genetic variation in space than on Earth. Was it the radiation? The microgravity? The loneliness of orbit? We don’t know—but the miso still tasted great.

4. A Bacteria Surprise: Meet Bacillus velezensis.

This friendly bacterium showed up only in the space batch, particularly near the surface. It’s common in fermented soy foods, but its cameo here suggests the miso developed a microbial twist—a little souvenir from the stars.

5. This Could Be the Future of Flavor.

This successful experiment proves that fermentation is possible in space. That means long-term missions could include not just preserved food but living, flavor-evolving foods. Kimchi on Mars? Soy sauce on the Moon? It’s all on the table—or will be.