While coffee is a popular drink all across the world, it holds a particularly special place in the hearts of Finnish people. According to the International Coffee Organization, Finns consume more coffee than any other nation in the world.

But like everywhere else, coffee consumption in Finland comes with a hefty waste problem. In fact, about 13 percent of household waste in the northern country consists of discarded coffee grounds. This is one of the disconcerting statistics that has inspired a Finnish footwear firm to incorporate caffeinated grounds into its sustainable trainers.

In a bid to reduce the humongous amount of coffee waste that ends up in landfills and emits planet-warming methane, footwear firm Rens has created waterproof trainers out of discarded coffee grounds.

“When we started, we actually realized that only five percent of the coffee waste in the world actually gets recycled,” says Rens co-founder and CEO, Jesse Tran. “Coffee waste is a bio waste, but it produces a lot of methane, which is like 32 times more potent than CO2. So what we do here is just extend the life cycle.”

Each pair of Rens’ first generation ‘Original’ trainers contain 300 grams of coffee grounds — the equivalent of about 21 cups of joe. According to Tran, the production process involves mixing the discarded coffee grounds with recycled plastic pellets, creating a material called “coffee polyester yarn,” which makes most of the upper part of their shoes.

To take their sustainability efforts further, Rens claims that it also offsets all emissions from production, packaging and distribution, making its products truly climate-neutral.