Imagine brewing coffee as a nightcap. That’s what Deland Jessop says he and his wife have begun to do with Counting Sheep Coffee—a new product designed to allow coffee lovers to drink a cup before bed without being kept awake for hours.

“Instead of a glass of wine, we’ll brew up a cup of coffee instead,” said Jessop, who launched the company in 2013.

When his wife complained that she couldn’t enjoy coffee after 3 p.m., Jessop turned his home into a makeshift lab to search for a possible solution. After experimenting with a variety of herbs and supplements, he says he stumbled upon valerian—a plant that has been used as a mild sedative in Europe for centuries. He mixed it with decaf to mask the pungent smell, and sleep coffee was born.

Jessop notes that Counting Sheep Coffee is a food product, not a drug to help with sleep. Valerian is approved by the Food and Drug Administration as a food ingredient.

Experts don’t know exactly why the plant such a potent sleep-inducer, but there’s little known risk of side effects (other than the obvious drowsiness), says University of California San Francisco associate professor Stephen Bent. “In the studies that have been done, it’s been show to be safe,” he says. “It has a long traditional history of being used to induce sleep.”

The product first appeared at Bed, Bath & Beyond in 2013, and is now sold in several regional supermarkets.

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Write to Justin Worland at justin.worland@time.com.