When Washington, D.C., announced it was busy preparing for a wintry mix by making a cocktail of road-coating beet extract last week, some people were understandably confused. Beets and streets do not compute. Salt and streets, on the other hand, has a nice ring to it — if only because that particular food-infrastructure pairing had a head start in the popular imagination as an effective way to stop cars from skidding during icy nights.
But D.C., like many cities, has long relied on a potion of beet-enhanced brine to coat its roads. The extract of sugar beets, when combined with traditional ice-melting chlorides, can be more effective at lowering the freezing point of water than salt alone (here’s how the chemistry works). It’s also more biodegradable and less corrosive to vehicles. Discovered by a Hungarian scientist in the 1990s, the just-add-beets method has spread across North America, joining a host of other agricultural byproducts — including pickle juice, cheese brine and leftover beer — sprayed on streets in a quest to cut the dangerous salt habit that highway departments have picked up.