I get how the anal adjacency of these glandular secretions makes castoreum repulsive to many people. But if it was being used in flavorings, I knew there was only one reason for it: It must be delicious. I also knew, from conversations I’d had with people who work in the flavor industry, that it was increasingly rare. Decades ago, you may have caught a whiff of castoreum in fancy store-bought vanilla ice cream, or tarting up some raspberry-flavored chocolate bon-bons. But the chance that there’s any beaver butt lurking in today’s “natural flavors” is vanishingly small.
Castoreum is a quintessential secret ingredient, something that made a flavor better and more interesting, while eluding recognition.
Humans have a long history of consuming castoreum. Since antiquity, it’s been hailed as a powerful medicine, a treatment for everything from epilepsy to constipation to spider bites. Roman women inhaled the fumes of smoldering castoreum in an attempt to induce abortions. Francis Bacon, the 16th-century English polymath, recommended snorting a bit of powdered castoreum as a cure for brain-fog.According to nature writer Ben Goldfarb, author of Eager: The Surprising Secret Life of Beavers and Why They Matter, the demand for castoreum wiped out most of the beavers in Europe by the end of the Middle Ages. When Europeans settled North America, with its abundant supply of beavers, they had another use for the animal: beaver-fur hats. Living beavers, a keystone species, helped build the American landscape; dead beavers provided a foundation for American capital accumulation, and helped fund Western colonization. The Astors made their original fortune in beavers, before getting into Manhattan real estate.
Castoreum was never fake vanilla or fake strawberry—not exactly. It was used in tiny amounts, usually less than ten parts per million, adding depth, intricacy, and intrigue to flavor compositions. In this way, castoreum is a quintessential secret ingredient, something that made a flavor better and more interesting, while eluding recognition.
In 1982, according to the Flavor Extract Manufacturers’ Association (FEMA), 683 pounds of castoreum were used in flavorings in the US. In 1987, that had dropped to just under 250 pounds.
Tamworth Distilling, makers of Art in the Age spirits and other heritage-hipster libations, were inspired to make a spirit with castoreum when they noticed it on the GRAS list, the tally of “generally regarded as safe” ingredients the FDA allows in food. Their Eau de Musc, released this summer, is a bourbon flavored with castoreum along with regional White Mountain botanicals: fir tips, sweet birch, wild ginger, Canadian snakeroot. It’s “the mood of the forest,” evoking both the beaver and its woodland home, according to Matt Power, a master distiller at Tamworth who helped develop the beverage.
Beavers are ferociously territorial, and castoreum is how they mark their territory. They build muddy mounds “about the size of an upside-down cocktail glass,” Kaska told me, back up to them, and squirt castoreum from out their glorious, multipurpose buttholes. To a beaver, castoreum is a complex chemical stew, one that advertises a beaver’s clan and tells non-relatives to keep out.
“I sell a plastic shopping bag full of dried frozen castors every month,” he told me, though he couldn’t quite say who’s buying them or why. “We don’t talk about who they are.”
Kaska finds himself killing more beavers lately. The price of pelts has collapsed, and with fewer hobby hunters to keep the population in check, beaver dams are a growing problem, flooding houses and washing out roads. He relocates beavers when he can, but crowded beavers slaughter each other over territory, or waste away from disease. Hunting them is kinder, he says. Nature is out of balance.Kaska tries to find a use for every part of the beavers he kills. He says beaver meat is delicious and tender, “like Black Angus steak tips.” When he can’t convince people to eat it, he donates it to a raptor sanctuary. He gives the skulls to science teachers. Using and appreciating castoreum, he says, is a way of honoring beavers.I pour myself a glass of Eau de Musc and try to taste the castoreum in it. It’s difficult; there’s a lot going on. It’s leathery and powdery, woody, slightly astringent, with a shadowy trace of berries. I try to imagine the slick, 50-pound beaver whose castor sacs infuse my glass of booze, and her busy life, cut short, in New Hampshire.