There’s a new buzzy booze making news out of New Hampshire. It’s not the grain bill, the price tag, the finish or even the fact that this bourbon is made so far north of Kentucky that’s giving it its 15 minutes of fame. Instead, it’s an unusual flavoring component that gives Eau De Musc its signature scent and taste. It’s called castoreum, a secretion harvested from the anal glands of beavers. And whether you realize it or not, you’ve likely consumed it in all manner of foods.
House of Tamworth, the distillery making the beavery bourbon, says that the castor sac excretions impart “bright and fruit qualities (raspberry) and rich leathery notes along with creamy vanilla aroma” upon their hooch. Which frankly sounds delicious. The only question is, why exactly does a glandular extract harvested from the backside of a beaver taste like raspberries and vanilla cream? And also, why is my mouth watering right now?
Castor sacs are a pair of glands located in subcutaneous cavities between the pelvis and base of the tail in beavers. Both male and female animals possess them, along with a second pair of anal glands. These two sets of glands work in tandem to release unique secretions that when combined, can be used among beaver communities for marking and communication. And while it’s the castor sac secretion – castoreum – that humans are chiefly interested in, the close proximity of all the glands and organs in a beaver’s – ahem – undercarriage, mean that the product we call castoreum also contains anal gland discharge and even urine within it.
Fur traders used to trap and kill beavers for their castor sacs, which were smoked after being removed. But for the past 100 years or so, humans have chiefly been interested in harvesting the extract from live beavers instead. Beavers, both male and female, have to be “milked” in order to capture their secret sauce, a process that involves first anaesthetizing the animals.
When it is successfully released, the secretion appears quite a bit like thinned out molasses – dark and thick and slimy. And it smells like, well, it smells a lot like vanilla, apparently. It turns out that bacteria in the gut is what chiefly gives most mammals’ waste and various secretions their displeasing odors. But beaver diets, consisting of specific leaves and bark, cultivate a biological flora that against all odds, smells more like the inside of a bakery.
So we eat it. Seriously. The Tamworth team is hardly the first company to toss a little castoreum into their recipe. The secretion has been used to flavor ice creams, sodas, candies, and other alcoholic concoctions in recent decades. Tracing its presence to a particular product today can be nearly impossible, however, as the U.S. Food and Drug Administration classifies castoreum as merely a natural flavor, an umbrella term that houses more than 3,000 different ingredients and chemical compounds.
One product that still proudly boasts its castoreum content is the Swedish schnapps Bäverhojt (Beaver Shout). Instagram is littered with home distillers who proudly display their castor sac-infused alcohol, along with a few brands that sell their own take on the stuff.
Though it smells sweet and sounds sickly, castoreum has long been used for medicinal purposes as well. It can be purchased in some pharmacies for use as a sleep aid. Salacin-rich castoreum is converted by human bodies into salicylic acid, which behaves much in the same way that aspirin does, to provide relief from pain.
Because artificial vanilla flavoring is so cheaply produced today, castoreum production has been driven off a cliff. Less than 300 pounds of the secretion is reportedly collected by food manufacturers each year. Of the castoreum that is still produced, the lion’s share is now used by the perfume industry. But with one plucky distiller using their beaver bourbon to prove that what’s old is new again, who knows what the future holds.