From Fleece to Grease
Once a sheep has been shorn, the fleece must be washed in a process called scouring. Scouring uses hot detergent solutions to remove the wool grease, which is a largely hydrophobic (water repellent) substance.
The wool grease is then recovered from the scouring liquids by high-speed centrifugation. Depending on the breed of sheep, the season and the quality of the wool, crude wool grease makes up about 10-15% of the weight of the shorn fleece.
Removing impurities and contaminants
Heavy impurities such as sand and dirt are removed by gravity settlement before centrifuging. To further reduce impurities such as sweat or environmental contaminants, the first wool wax concentrate is emulsified in hot water and centrifuged a second time.
The obtained substance is 'crude wool grease' or 'neutral wool grease'; this is then refined to produce lanolin, the most common wool grease product.