Twenty years ago, Steven Grasse married the flavors of cucumber and rose into what has become one of the world’s most beloved gins, Hendrick’s. Now, two decades later, he’s experimenting with a spirit that incorporates a more unusual ingredient: castoreum—or, to be graphically precise, the anal secretions a beaver uses to mark its territory.
“I have always been intrigued by the use of castoreum in food and luxury products,” says Grasse. “There was a time when it was used widely as a scent or flavoring agent in perfumes and food.” When he learned the ingredient was FDA-approved as a spirit additive, Grasse tested its flavor in bourbon to great success.
The result is Eau de Musc, (French for “Water of Musk”), and it’s produced by Grasse’s newest venture, New Hampshire’s Tamworth Distilling. The 88-proof bourbon has notes of leather, vanilla and raspberry thanks to the addition of beaver castor sac discharge.
This isn’t the first time Grasse has experimented with unusual flavor combinations. Tamworth recently released a cordial made with trumpet mushrooms and blueberries under its sub-brand, Art in the Age, which tests out unsung recipes inspired by native New Hampshire ingredients.
Grasse says that everything he creates at Tamworth is rooted in American history, and with castoreum’s centuries-old history as a treatment for maladies and later as an ingredient in perfumes and foods, plus the fact that beavers are a native New Hampshire species, creating Eau de Musc fit perfectly with the Tamworth brand.
According to Grasse, using extracts from the beaver castor gland can be traced back to the 12th century. He explains that during the 1800s castoreum was used to treat headaches, pain and fevers. Over the last hundred years, the ingredient became widely used in perfumes, where it’s beloved for its mysterious, musky scent. Today, fragrances like Chanel Antaeus, Givenchy III and Lancôme Caractère currently incorporate beaver secretions.
In the early 1900s, producers of vanilla-, raspberry- and strawberry-flavored foods, especially ice cream and gum, commonly added castoreum for its fruity and vanilla taste. But today, with an endless list of cheap food flavorings on the market, the ingredient has fallen out of vogue, partly due to its difficulty to procure and high price.
“You essentially need to ‘milk’ a beaver to the get the fresh secretions from the gland,” says Grasse, who responsibly sources his castor glands from an experienced local beaver trapper.
But castoreum continues to prove popular in luxury perfumes. And those leathery-raspberry notes are one of the key reasons why Grasse was keen to add it to whiskey. He explains that such aromas are common among barrel-aged spirits. “They were a great way to link the oak barrel components of vanilla, caramel and spice to the beaver’s contribution,” he says.
To prepare Eau de Musc, Tamworth infuses beaver castor sacs, along with birch oils, Canadian snakeroot, fir needles and raspberries in a neutral grain spirit composed of yellow corn, rye and malted barley.
Despite the off-putting nature of eating or drinking beaver secretions, when it comes to whiskey, Grasse says the two blend together harmoniously, yielding a spirit with a surprisingly mild and familiar taste.
“The reality is castoreum acts to fortify good whiskey flavors,” says Grasse. Its vanilla nose is complemented by the birch oil and wild ginger’s spicy notes, with scents of raspberry that impart a fruity nature.