The Intriguing Story of Castoreum: Beaver Secretions as a Flavor Enhancer

In September 2013, the well-known blogger 'The Food Babe' shared a video claiming that beavers 'flavor a ton of grocery store foods with their butthole secretions!' This sparked a wave of sensational posts online, suggesting that beaver-derived substances are used to flavor everything from sodas to vanilla ice cream. The focus of this controversy is a flavoring agent known as castoreum—but what is it, and does it deserve the attention it’s getting?

What exactly is castoreum?

Castoreum is a natural substance produced by both male and female beavers in Alaska, Canada, and Siberia. It is secreted from glandular sacs located near the base of their tails (the term castor comes from the Latin word for beaver). While beavers have limited vision and hearing, their sense of smell is highly developed—and their castoreum glands contribute to their distinct scent. They use this secretion to mark their territory, often depositing it on dirt mounds near their habitats. (The sound of castoreum being expelled is so distinct that it can be heard by those standing close by.) Additionally, beavers rely on this oily, waxy substance to keep their fur waterproof.

With a scent blending vanilla, raspberry, and subtle floral notes, castoreum conveys details about a beaver’s well-being and helps differentiate between family members and strangers. This aroma is so captivating to beavers that, historically, fur trappers used it as bait in their traps.

The History of Castoreum

Fresh castoreum is a liquid that varies in color from yellowish and milky to gray and viscous, depending on the beaver’s species and gender. In live beavers, the fluid is extracted, dried, and processed into a solid for use in perfumery. In deceased beavers, the entire castoreum gland is harvested and traditionally preserved by smoking it over a wood fire.

Throughout history, castoreum served as a medicinal remedy. Roman women would inhale the smoke from burning castoreum in lamps, believing it could cause abortions (though it did not). Hildegard von Bingen, a renowned 12th-century Benedictine abbess, mystic, and scholar, claimed that consuming powdered beaver “testicles” mixed with wine could lower fevers (the dried castoreum gland is often confused with testes). Additionally, castoreum was used to alleviate headaches, which is logical given its salicylic acid content, the key component in aspirin.

The colonization of America boosted the supply of beaver pelts, which were highly sought after for making luxurious hats across Europe. This also revived interest in castoreum as a medicinal substance. Available in drugstores and pharmacies, it was prescribed for ailments like earaches, toothaches, colic, gout, insomnia, excessive sleepiness, and overall brain enhancement. By the 19th century, castoreum found its way into the perfume industry as a fixative, enhancing and prolonging the fragrance of other scents.

By the late 19th century, the high demand for beaver pelts and castoreum pushed North American beavers to the brink of extinction. In 1894, a representative from the Hudson Bay Company, a leading trader in beaver pelts and castoreum, remarked: “The beaver’s days are numbered. It cannot survive alongside civilization.”

Is castoreum still in use today?

As noted in The Oxford Companion to Sugar and Sweets, castoreum was initially used as a food additive in the early 20th century but is now scarcely used in large-scale flavor production. However, the FDA classifies it as a “natural flavor” due to its natural origin. It can impart fruity notes like strawberry or raspberry or serve as a vanilla substitute (the compounds originate from the beaver’s diet of bark and leaves). One of the few places it is consistently found is in the Swedish schnapps BVR HJT.

Beavers are no longer commonly hunted for their pelts or castoreum. To obtain the substance, humans must anesthetize the beavers and extract the castoreum from their glands. Joanne Crawford, a wildlife ecologist at Southern Illinois University, described the process as “pretty gross,” noting that the substance has a molasses-like consistency. Due to the difficulty and cost of harvesting castoreum from live beavers, its use has become rare. Fenaroli’s Handbook of Flavor Ingredients reports that annual consumption of castoreum is minimal—around 300 pounds—compared to over 2.6 million pounds of natural vanillin. When used, castoreum is more likely to appear in the fragrance industry than in food products.

“The flavor industry requires massive quantities of raw materials,” flavor chemist Gary Reineccius explained to NPR’s The Salt. “You can’t cultivate beavers in fields for harvesting. Their numbers are limited, making castoreum an expensive and impractical option for food companies.”

While it’s difficult to identify which foods or fragrances contain castoreum, its presence is extremely rare. Instead of worrying about this obscure ingredient, it might be better to focus on other concerns—or simply appreciate the beaver’s unique contribution.