You Might Be Knitting With Gelatin Soon

Slaughterhouse yarn
All the ingredients for "slaughterhouse yarn" ETH Zurich, Functional Materials Laboratory


It may not sound like haute couture, but "slaughterhouse yarn," fibers made from agricultural byproducts such as gelatin, keratin and casein, may soon be recycled into a new 'offal' fashion trend. 

The textiles made with animal byproducts are said to be as luxurious as cashmere, and the yarn is being compared to two-ply weight merino wool. If it makes it from the lab to reality, it could reduce the volume of livestock waste products and decrease the pollution created during the manufacturing of synthetic fabrics like polyester and nylon, which are derived from fossil fuels.

Philipp R. Stoessel, a Ph.D. student in Professor Wendelin J. Stark's Functional Materials Laboratory (FML), in Zurich, Switzerland, successfully turned biological waste into gelatin-based yarn, according to a report recently published in the journal Biomacromolecules.

Yep, we're talking about gelatin, that biomaterial made from the collagen in the skin, bones and tendons of cows, sheep and pigs primarily. It's also been the key ingredient in Jell-O since 1897 (and other desserts, too), and now it's been fabricated into yarn, thanks to Stoessel. He and the FML research team collaborated with the laboratory of Advanced Fibers at EMPA (Swiss Federal Laboratories for Materials Science and Technology) in Dübendorf, Switzerland.

Getting From Meat to Mittens

During the experiment, the team discovered that when an organic solvent, in this instance, isopropyl, is added to a heated solution of deionized water and porcine gelatin (an aqueous gel solution), the protein does something interesting: It precipitates and settles to the bottom of the beaker. Agitate it with a pipette and the mass can be shaped into a long, thin fiber.

To begin fabricating the fiber, they removed the mass of gelatin at the bottom of the container and, with a syringe, extruded individual fibers onto Teflon-coated rollers in an ethanol bath to prevent individual filaments from sticking and to encourage the gelatin to harden.

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Ultra-thin threads of the biomaterial get doused by ethanol-soaked rollers.
ETH Zurich, Functional Materials Laboratory

With a proprietary spinning machine, the researchers produced as much as 656 feet (200 meters) of fiber every 60 seconds. With a hand spindle, they twisted as many as 1,000 fibers only half the thickness of an individual human hair into a usable skein of yarn. Then came the actual knitting.

There's an immediate visual and tactile difference between the wool and gelatin fibers, according to the researchers. While, wool feels scratchy and rough to the touch, the mittens crafted with the gelatin yarn felt smooth and had a noticeable luster not seen on the wool pair.

There is one current disadvantage of slaughterhouse yarn: Gelatin fibers are water-soluble, a property not normally welcome in clothing. To achieve water resistance similar to that of wool, the research team processed the yarn first with an epoxy resin, then treated it with formaldehyde to increase its durability and strength while decreasing its absorption properties. They also used lanolin to give the yarn a supple feel. Stoessel plans to conduct additional studies on methods of increasing the water-resistant properties of gelatin yarn until the end of his doctoral program.

Crafty Types Respond

"I think it is an interesting idea," says Suzanna Bibens, a nurse, mom of four, and beginning knitter who is partial to wool and cotton fibers. "The aspect of reducing waste, including animal waste, is valuable. In reality, though, I would have to feel and smell the skein of yarn or the fabric itself to know if I would buy it."

However, Nancie Meng, a long-time quilter and grandmother of three, wasn't sold.

"Offal sounds awful," says Meng.

Stoessel and fellow researchers Robert N. Grass and Wendelin Jan Stark were named the inventors of the spinning and the extrusion process used to create individual strands of gelatin fibers in a patent filed in 2014.