Wet-Finishes for Yarn: It All Comes Out in the Wash

Looking at a piece of beautiful handblown art glass, it’s hard to believe that what we see is in constant motion. The windows in a bank building or supermarket are all actually flowing like water. We can’t see it happen—it moves too slowly for the human eye to record it. But move it does, causing the ripples and waves found in old glass windows and sometimes causing art glass to fly apart as the glass moves in conflicting currents. What is true for glass is equally true for yarn. It’s always moving, governed by one of the basic principles of textiles that all fiber will try to return to its natural state.

When we spin, no matter what method we use or what fiber we spin, we distort the natural order of the fiber. We do this primarily by introducing twist into the fiber, but we also, during the spinning process, elongate the fiber and straighten out the natural crimp structure. Once the spinning process is over, the fiber in the yarn tries to move back into its original shape. Our job as yarn designers is to decide how to keep the movement in the yarn to a minimum or use it to our advantage. We do this by using a number of finishing methods either to stop the untwisting of the fiber (setting the twist) or to increase the movement of the twist to force the yarn to open up and bloom (fulling). Sometimes we also try to prevent the crimp from returning by drying it under pressure (blocking). There are many variations and combinations of these finishing techniques, but they all have one thing in common—they use water to control and change the yarn.

Left: Before and after samples of yarn texture created by differential fulling in a plied yarn—the silk singles buckles to create a loop because it doesn’t full, and the Corriedale singles does full, and in doing so it gets shorter and wider. Right: Fulling a skein of Rambouillet in hot, soapy water with a plunger for extra agitation. Photos by Joe Coca

What is wet-finishing?

Wet-finishing simply means that water is used to relax the crimp and set the twist. Wet-finishing techniques range from something as simple as a gentle wash in soap and warm water to more complex methods involving agitation and extreme changes in water temperature. The end result of these techniques will depend on the type of fiber and spinning method you have chosen.

All yarns, whether they are tightly or loosely spun, whether they are woolen or worsted, lose twist when they enter water for the first time. It can be cold water or hot, plain or soapy—even water in the form of steam—and it can be after the yarn has been made into a garment or fabric. In all cases, twist will be released and redistributed. Also, when the yarn is supported in water, the tension it has been under in the spinning process is removed and the yarn relaxes, regaining much of its original crimp structure.

While there can be as many variations on wet-finishing as there are spinners, there are three main methods: soaking (twist setting), soaking and agitation (fulling), and drying under pressure (blocking).

Photos by Joe Coca

Examples of wet-finishing shown above

Top Row:
1) It is best to set the twist of these Mohair (a) and silk (b) fibers (once spun up into yarn) in a simple warm-water bath because they both have very little crimp structure.

2) This qiviut was spun for lace. The one that was poorly dehaired (a) has loops because the long fibers didn’t full. The second skein (b) comes from the same batch of qiviut fiber, but it was properly dehaired and spun.

Bottom Row:
1) 2-ply skeins of Rambouillet and kid Mohair, fulled (a) and not fulled (b).

2) Qiviut 2-ply for lace. The first qiviut skein has been fulled and is rounder and softer, and the twist is more even (a). The second one has not been fulled (b).

What’s right for your yarn?

The finishing technique will have a long-lasting effect on your yarn and the project you make with it. With so many options to choose from, how do you find the technique that is just right? First, examine the fiber you are using. Fibers have a natural response to different finishing techniques. Some, like silk, respond with hardly any change at all. Others, like cashmere and angora, are astonishingly different after finishing.

Generally, fibers are divided for finishing into two main groups by the length of the staple (staple is the naturally occurring division of the fibers in a fleece) and the amount of crimp (the natural waves) per inch in the staple.

Long fibers (longer than 3 inches) usually have low crimp—fewer than seven crimps per inch. When you apply water, heat, lubrication, and agitation, these fibers tend to move toward the center of the yarn, becoming denser and stronger. Taken too far, these fibers would have a serious risk of felting. Luster longwools such as Romney, Lincoln, and Cotswold are good examples of fibers that fit this description. Silks, bast fibers like hemp and flax, Mohair, and type A pygora (the pygora fleece that closely resembles an ultrafine Mohair) are also in this group. While there are other factors, such as the spinning method used, the finishing technique these fibers respond to best is twist setting.

Short fibers (2½ inches or shorter) commonly have a greater number of crimps per inch than seven, making them much more elastic. When you finish these fibers, they move away from the center of the yarn, allowing the ends of the fiber to stick out and creating a haloed surface. They generally regain much of their original crimp, which pushes the yarn open and gives it a larger diameter. Cashmere, yak, bison, qiviut, and angora are examples of fibers in this group. So are Merino, Cormo, Rambouillet, and robust crimp breeds like North Country Cheviot, Dorset, and Southdown. As for the long, low-crimp fibers, the effect of finishing will be influenced by how the fiber is prepared and spun. Taking these factors into account, the technique that is most effective with these fibers is fulling.

There are, of course, exceptions to how fibers react.

Photos by Joe Coca

Examples of wet-finishing shown above

Top Row:
1) Wet-spun singles (a) and a Möbius scarf (b), 50% fine Merino and 50% silk spun as a loose singles and then fulled in a top-loading washing machine. The Möbius scarf has been worn for about three years and shows none of the wear or pilling you would expect.

2) Two fibers that do well fulled: white Corriedale (a) and natural brown Shetland (b). These both have a fairly high crimp and will expand and soften during fulling.

Bottom Row:
1) This Turkish knot yarn needs to be blocked to make all of the layers of twist balance (a). Now it will make a wonderful warp yarn (b).

2) Before (a) and after (b): this silk yarn is just off the bobbin and set in warm water during the dyeing process—the twist is slightly released and evened in the water.

Read Judith’s complete article, orginally published in Spin Off Summer 2027, which includes details on fulling (including differential fulling and accidental fulling), blocking, felting, effects during the dyeing process, how treated fibers react, and more in this special bonus for current subscribers to Spin Off. Log in or follow the link below to get your download.

Wet-Finishes for Yarn PDF Download