A Shade of Pink

Story by Debby Waldman

In an annual event called Heifer in Your Tank, students in Frank Robinson’s Animal Science 200 class at the University of Alberta present the answers to unusual questions about agriculture. Here we discover the truth about what’s in those crayons your child draws with

The question: What parts of pigs make crayons?

The short answer: Just about every part that you won’t find for sale at your local butcher shop.

   Crayons contain three primary ingredients. Paraffin wax, a colourless petroleum by-product, provides the foundation. Pigment, from a variety of non-organic compounds, provides the colour. Stearic acid, made from animal or vegetable fat or through synthetic processes, helps to make the crayons hard. Pigs are among the animals that produce stearic acid.

   Here’s how it works. Stearic acid is derived through a process called rendering. All the trimmed pork bits that aren’t saleable – eyeballs, hoofs, fat from around the intestines and the hide – are processed together. During the processing, the fats that rise to the top are called tallow. One of the fats extracted from tallow is stearic acid.

   There’s enough stearic acid in one 100-kilogram pig to make 75,000 crayons. Collecting stearic acid from all the pigs in Alberta could yield 255 billion crayons in one year. Robinson calls it “recycling,” and as with recycling, everything is used.

  But no matter what goes into them, kids are likely to contiue doing what they've done for decades: cracking open a fresh pack of crayons, picking out their favourite colours and making beautiful art.