Skip to Content

Beaver Castor

November 21, 2011

By Ron Lancour
Beaver castors are quite valuable to the trapper if removed and handled properly. Although they are often called castor glands, they are not glands in the true sense of the word. The castor sacs are located between the pelvis bones of both male and female beaver along with the oil glands. For the commercial market only the castor sacs are of value. The oil glands are used mainly by trappers as a scent additive.

In the early 18th century beaver castor (castoreum) was believed to have many medicinal properties. Today it is an important ingredient used by the perfume industry. In perfume making, the term castoreum is more liberally applied to denote the resinoid extract resulting from the dried and alcohol tinctured beaver castor. The dried beaver castor sacs are generally aged for two or more years to mellow and for their raw harshness to dissipate. In perfumery, castoreum has largely been used for a leathery scent.
Trappers also use castor in scent and lure preparation to be used at trap sets. Some minor uses are as a food additive, which is approved by the U.S. Food and Drug Administration.

Beaver castors are sold by private treaty to a limited customer base. If sold at auction, the expenses of buyers to attend the auction would considerably drop the price per ounce. The primary buyers are the European perfume industry. Some castors are sold into Pakistan and India but we are not sure of their use by those countries.

In the handling of beaver castors, NAFA does not deduct a flat percentage rate for shrinkage. Castor packages are opened and the castors spread in individual screen drying racks or hung in mesh bags. Castoreum continues to shrink and dry, Number 1 castors will always have a moisture content. Once a castor order is received or negotiated the castor is then weighed, graded, shipper documented and packed for shipping.

There are three grades of castor.
#1 Castors that are clean, full pods and no holes.
#2 Ordinary, castors with holes, large castors with only small amounts of castoreum in the pods and castoreum that is too dry to be #1.
#3 Castors that are small, shells, and castor that is too poor to be #2.

Once the beaver has been pelted the castors can be located between the pelvic bones at the base of the tail. Lift the meat above the castor and make a small cut, careful not to cut the castor sac. Then use your fingers peel away and separate the meaty membrane and fat from the castor sac. Repeat on the other side. Now you have two pods attached in the middle. Cut away from the carcass so as to keep the pods intact. Give them a twist to close off the opening. DO NOT tie them with wire or string. Do not remove the oil glands with the castors; there is no commercial market for these.

The pods can now be hung up to dry over a nail or wire. Turn the pods after a couple of days so as to dry the part where the two pods were touching. They can also be dried on a wire screen rack. Dry in a well ventilated spot. Turn frequently to ensure equal drying and drying spots that may be touching each other. After six to ten days the castors can be wrapped in newspaper, put in a plastic bag, and frozen in a deep freeze.

A couple of days prior to shipping remove them from the deep freeze and spread out to dry the accumulated frost. Once dry wrap in newspaper, burlap, or a mesh bag (onion sack) and then pack in a cardboard box for shipping. DO NOT ship in a plastic bag, and DO NOT ship wet castors, they will spoil (rot) in shipping.
If you have any questions for Ron Lancour, email him at