Future Mars Settlers Could Make Good Wine, But Heavy Metal Drinking is Bad

In The Martian, astronaut and icon of interplanetary tardiness Mark Watney gets by with some protein bars and poop-grown potatoes. That’s plausible, from what we know about botany, but let’s say we want to do better than that. Let’s say we’re shooting for more than survival. What would Mars wine taste like?

First off, scientists think that, given appropriate climate control and watering, we could grow grapes on Mars. But what makes the rocky dust covering the planet — known as regolith — unlike Earth’s soil is the relative lack of organic compounds. “All basic nutrients are present, but nitrate and ammonia, both essential for plant growth are rather scarce,” Wieger Wamelink, an ecologist at Wageningen University in the Netherlands, tells Inverse. Still, there are sufficient amounts of phosphorous, potassium, calcium, magnesium, and iron. “The lack of nitrogen in the soil is solvable by applying nitrogen-fixing plants or better bacteria that live in symbiosis with the plant.”

Wamelink knows about how tough it is to grow crops on Mars, because he’s come as close as anyone.In 2014, Wamelink and his colleagues published a report in PLoS One demonstrating they could grow wheat and tomatoes in simulated regolith from a company called Orbitec (it’s categorized, charmingly, as a Space Resource. In fact, the Mars soil simulant held more water than actual soil.

But the research comes with a few caveats. Though Wamelink says the mineralogy of the simulated Mars regolith is on point, there are other agricultural factors. “Plants use nutrients that are dissolved in water,” he says, “and that has never been tested for the Martian soils.” Nor is it clear if the fruits of their labor are any good. “We cannot eat them yet, since we are not sure that it is safe to do so,” he says. “There are quite some heavy metals present in the soil and we must be certain that they are not also present in the fruits before we can eat them, otherwise they may harm our health.”

Heavy metal contamination is a real problem — elements like cadmium, absorbed from the soil, can accumulate in plants at unsafe levels for animal or human consumption. Say Wamelink’s tests come back clear, and so do the inevitable NASA experiments: Would we enjoy drinking what comes out of the Martian garden?

That the land is reflected in wine is an old wine-making concept, called terroir. There’s not a ton of conclusive evidence that terroir alters wine’s aromatic compounds. But there is some indication that trace elements can be found in wines from certain regions, which Earth Magazine likens to chemical fingerprinting.

It turns out that Martian regolith — the simulant, anyway, looks a bit like loess, a sandy soil Wamelink’s familiar with, as it covers the southern Netherlands. It’s also where Netherlands’ grapes are grown for the production of wine, he says. “So if the taste would be similar, it could be quite good. Since the taste of the soil is very much reflected in the wine, I suspect that Martian wine will have its own specific taste.”

There’s just one last problem: “Export of it to Earth, though, would be rather expensive,” Wamelink says. At about $10,000 a pound to get something into space, a 3-pound bottle of wine would come with at least a $30,000 shipping cost. Though actual wines have been purchased for $15,000 a pop, so who’s to say there wouldn’t be an oenophile with a fat budget and a hankering for an extraterrestrial vintage?