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A Brief History of Castoreum, the Beaver Butt Secretion Used as Flavoring

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In September 2013, popular blogger “The Food Babe” released a video proclaiming that beavers “flavor a ton of foods at the grocery store with their little butthole!" Since then, the internet has been crowded with alarmist posts saying that beaver’s butts are used to flavor everything from soft drinks to vanilla ice cream. The culprit behind this scare is a flavorant called castoreum—but what exactly is it, and is it worth all the fuss?

WHAT IS CASTOREUM?

Castoreum is a substance secreted by male and female Alaskan, Canadian, and Siberian beavers from pouchlike sacs located near the base of their tails (castor is the word for beaver in Latin). Beavers can’t see or hear very well, but they have a great sense of smell—and as a result of their castoreum glands, they also smell great. They use their castoreum in part to mark their territory, secreting it on top of mounds of dirt they construct on the edges of their home turf. (The castoreum squirting out is apparently so loud, you can hear it if you’re standing nearby.) Beavers also use the fatty, waxy secretion to waterproof their fur.

An odorous combination of vanilla and raspberry with floral hints, castoreum carries information about a beaver’s health and helps to make distinctions between family members and outsiders. Beavers are so interested in the smell that historically, fur trappers would bait traps with castoreum.

HOW WAS IT USED?

Dried castoreum on display in a German museum
Dried castoreum on display in a museum.

When castoreum is fresh, it’s a fluid that ranges in color from yellow and milky to grey and sticky, depending on the type of beaver and its gender. In a live animal, this fluid is milked and dried to a solid for perfume making. In a dead animal, the entire castoreum gland is removed and, traditionally, preserved by smoking it over a wood fire.

For much of its history, castoreum was used as a medicine. Roman women inhaled the fumes of castoreum burned in lamps because they believed it would induce abortions (it didn’t). Hildegard von Bingen, a 12th-century Benedictine abbess, mystic, and scholar, wrote that powdered beaver “testicles” drunk in wine would reduce a fever; the castoreum gland, when dried, is easily mistaken for testes. Castoreum has also been used to treat headaches, which makes sense given that it contains salicylic acid, the main ingredient in aspirin.

The colonization of America led into an increase in the availability of beaver pelts, which were used to make fine hats all over Europe, and to a resurgence of interest in castoreum as medicine. Sold in drugstores and pharmacies, it was recommended for earaches, toothaches, colic, gout, inducing sleep, preventing sleep, and general strengthening of the brain. It was also in the 19th century that the substance began to be used in the perfume industry as a fixative—an ingredient that makes other scents smell better and last longer.

By the end of the 19th century, the demand for pelts and castoreum was so great that North American beavers were on the edges of extinction. In 1894, a representative of the Hudson Bay Company, a major beaver pelt and castoreum trading firm, said: "The beaver’s days are numbered. He cannot coexist with civilization.”

IS IT STILL BEING USED TODAY?

According to The Oxford Companion to Sugar and Sweets, castoreum was first used as a food additive in the early 20th century, but is now rarely, if ever, used in the mass-produced flavor industry. Nevertheless, the FDA considers it a “natural flavor,” since it is derived from a natural source, and can be used to add fruity strawberry or raspberry notes, or as substitute for vanilla (the compounds come from the beaver's diet of bark and leaves). One of the few places it's reliably found is the Swedish schnapps BVR HJT.

Beavers are generally no longer hunted for their pelts or castoreum, so to acquire the sticky stuff, beavers must be anesthetized and the castoreum gland milked by a human. The process was described as “pretty gross” by Joanne Crawford, a wildlife ecologist at Southern Illinois University who is no stranger to beaver butts; she noted that the goo has a consistency somewhat like molasses. Due to the inconvenience and expense of harvesting castoreum from live beavers, the substance is now seldom used. According to Fenaroli’s Handbook of Flavor Ingredients, the annual industry consumption is very low—around 300 pounds—whereas the consumption of natural vanillin is over 2.6 million pounds annually. When castoreum is used, it's far more likely to be in the profitable fragrance industry rather than in the foods we eat.

"In the flavor industry, you need tons and tons of material to work with," flavor chemist Gary Reineccius told NPR's The Salt. "It's not like you can grow fields of beavers to harvest. There aren't very many of them. So it ends up being a very expensive product—and not very popular with food companies."

So while it's hard to know what foods or fragrances contain castoreum, there is very little of it out there. It may be worth saving your alarm for another topic—or simply sparing a thought for the beaver.

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TASCHEN
Everything You Need to Know About Food in One Book
TASCHEN
TASCHEN

If you find yourself mixing up nigiri and sashimi at sushi restaurants or don’t know which fruits are in season, then this is the book for you. Food & Drink Infographics, published by TASCHEN, is a colorful and comprehensive guide to all things food and drink.

The book combines tips and tricks with historical context about the ways in which different civilizations illustrated and documented the foods they ate, as well as how humans went from hunter-gatherers to modern-day epicureans. As for the infographics, there’s a helpful graphic explaining the number of servings provided by different cake sizes, a heat index of various chilies, a chart of cheeses, and a guide to Italian cold cuts, among other delectable charts.

The 480-page coffee table book, which can be purchased on Amazon for $56, is written in three languages: English, French, and German. The infographics themselves come from various sources, and the text is provided by Simone Klabin, a New York City-based writer and lecturer on film, art, culture, and children’s media.

Keep scrolling to see a few of the infographics featured in the book.

An infographic about cheese
TASCHEN

An infographic about cakes
Courtesy of TASCHEN

An infographic about fruits in season
Courtesy of TASCHEN
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'Lime Disease' Could Give You a Nasty Rash This Summer
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A cold Corona or virgin margarita is best enjoyed by the pool, but watch where you’re squeezing those limes. As Slate illustrates in a new video, there’s a lesser-known “lime disease,” and it can give you a nasty skin rash if you’re not careful.

When lime juice comes into contact with your skin and is then exposed to UV rays, it can cause a chemical reaction that results in phytophotodermatitis. It looks a little like a poison ivy reaction or sun poisoning, and some of the symptoms include redness, blistering, and inflammation. It’s the same reaction caused by a corrosive sap on the giant hogweed, an invasive weed that’s spreading throughout the U.S.

"Lime disease" may sound random, but it’s a lot more common than you might think. Dermatologist Barry D. Goldman tells Slate he sees cases of the skin condition almost daily in the summer. Some people have even reported receiving second-degree burns as a result of the citric acid from lime juice. According to the Mayo Clinic, the chemical that causes phytophotodermatitis can also be found in wild parsnip, wild dill, wild parsley, buttercups, and other citrus fruits.

To play it safe, keep your limes confined to the great indoors or wash your hands with soap after handling the fruit. You can learn more about phytophotodermatitis by checking out Slate’s video below.

[h/t Slate]

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