Mercerized Wool: Enhanced Luster and Hand

Mercerized wool has a silky luster, the softness of cashmere, and takes dye beautifully.

Joy Selby Cain Nov 6, 2020 - 9 min read

Mercerized Wool: Enhanced Luster and Hand Primary Image

Mercerized wool is Merino fiber that has been chemically altered to enhance the luster and hand of the yarn. Photos by Joe Coca

I was helping my friend Kim Semler of Lucky Cat Craft run a booth at A Wool Gathering in Yellow Springs, Ohio, when she handed me a bag. “Here, try this! It’s mercerized lambswool.” I felt the fiber and bought all of it.

Most weavers are familiar with mercerized cotton. When cotton yarn is mercerized to enhance the luster of the cotton during commercial manufacturing, it is chemically altered by bathing it in sodium hydroxide solution, then neutralized in an acidic bath. The yarn is then quickly passed through a flame to remove stray fibers. The result is a lustrous yarn that takes dye very well and has a softer hand than unmercerized cotton.

Mercerized wool is not so different in that the goal is a lustrous fiber that takes dye well and has wonderful drape. Mercerized wool starts with Merino fleece. The scales are removed through rapid chlorination (in a closed system) followed by the application of a silicone polymer. While the diameter of the fiber does not change, the fiber feels finer than the original wool.


Mercerized wool has a silklike luster and the softness of hand of cashmere. Because it has had the scales removed (and has been through a chemical alteration process similar to that for superwash wool), it will not felt. However, mercerized wool has an entirely different hand than either superwash or Merino top. It does not have as much loft as untreated wool, and the drape of the finished item is more like silk than wool.


Handling the fiber is a little challenging. The fiber will drift away from the top and separates easily. This can be used to your advantage when stripping the fiber for fine spinning. This characteristic also gives a slight halo to your yarn and your finished product.

Dyeing mercerized wool

Mercerized wool takes dye beautifully but must be handled carefully. I like to use acid dyes after the fibers soak for at least 4 to 8 hours. Like silk, the mercerized wool top can be quite dense, and a longer soak will help the dye penetrate all the fibers and yield better results. Handle it as little as possible during the dye process because the fiber can be slippery and can pull itself apart. I use a colander to pull the fiber out of the water bucket so the wool stays together.

If you are painting the dye onto the fiber, again you want to handle it as little as possible. Gently soak a sponge brush and tap the fiber. Turn the fiber over and apply more dye to make sure the dye penetrates all the way through.


While mercerized wool can be spun using a short draw, I’ve had more success with a modified long draw. My spinning method is to draw out the fiber with my left hand, pinching near the orifice with the right hand and drawing out the fiber a bit more with the left to eliminate slubs. My long draw is also fairly short—about 6 inches. Mercerized wool requires more twist due to the lack of scales. I use the smallest whorl on my wheel and treadle an extra couple of times to make sure it stays together.

I like to spin fine and ply to get the diameter yarn I want. As a weaver, I usually make and use two-ply yarns. However, for one mercerized wool project, I wanted a three-ply yarn and tried to chain-ply the singles. I didn’t start with enough twist in the singles for chain plying, and the yarn untwisted and fell apart. When I plied the same singles from three bobbins though, the yarn plied beautifully.

I noticed there was a difference when I spun from one end of the top as opposed to the other. If you are getting a lot of slubs, flip the fiber over (similar to spinning from the butt or tip end of a staple), and you should end up with a smoother yarn.


Sample 1: Woven swatches, 3-ply (19 wpi; 1,900 ypp). Sample 2: Crocheted flower medallion from the chain-plied yarn (24 wpi; 2,400 ypp); crocheted flower medallion from the 2-ply yarn (30 wpi; 3,000 ypp); and mercerized wool.

Sample 1

I weighed out an ounce of top and divided it evenly into thirds (one for each ply). I held 3 inches of top in my left hand and spun on a supported spindle with the right (my dominant hand). I would stop and pull back the fiber with the left hand for a semilong draw, add more twist with the right hand, and wind on. After I finished spinning each third, I wound the yarn onto a bobbin using a bobbin winder. I plied the yarn on my spinning wheel. The singles measured 35 wraps per inch, and the three-ply yarn measured 19 wraps per inch.

I wove the Corduroy pattern (from Licia Conforti’s Modular Textures: Patterns for the Weavette & Weave-It Looms, Volume 1, 2006) on a 4-by-4-inch pin loom and was pleased with how the yarn filled in.


Sample 2

I wanted to see the difference between crocheting with a two-ply yarn and a three-ply yarn. I also wanted to spin a fine singles for crochet lace. For the singles, I split the fiber lengthwise into 1⁄4-inch-wide strips. Using the smallest whorl on my lace flyer (35:1 ratio), I spun long draw in the Z direction, concentrating on not drafting too far apart (to prevent the singles from drifting apart). I added an extra treadle of twist before winding onto the bobbin.

With a single bobbin of singles, I thought I would chain-ply instead of separating the yarn onto three bobbins. I had a lot of breaks before I realized why the yarn was falling apart—I hadn’t inserted enough twist to spin a chain-plied yarn from the mercerized wool that has had all the scales chemically removed from the fiber. The twist in the opposite direction travels up into the singles and can rapidly pull it apart. I plied about half an ounce before I threw in the towel. The result was a three-ply yarn that measured 24 wraps per inch.

I spun the remaining singles, split the yarn between two bobbins, and plied from my lazy kate. I had no trouble with breakage and soon had a lovely two-ply yarn that measured 30 wraps per inch.

I finished both yarns with a hot soak in water, squeezed out the excess water by wrapping the yarn in a towel, and then hung the skeins to dry with weight.

I crocheted flower medallions to embellish a headband for my daughter. I found the perfect flower: Blossom in The Harmony Guides: 101 Stitches to Crochet (Interweave, 2008). I used a size 4 crochet hook for the two-ply and a size 1 hook for the three-ply.

I love the feel of mercerized wool and the pieces I made from the spun yarn. It was a joy to spin, and the resulting yarns were true luxury.


  • Conforti, Licia. Modular Textures: Patterns for the Weavette & Weave-It Looms, Volume 1. Williamstown, Massachusetts: Buxton Brook Looms, 2006.
  • Knight, Erika. The Harmony Guides: 101 Stitches to Crochet. Loveland, Colorado: Interweave, 2008.

Joy Selby Cain works as a graphic designer by day, and by night, she spins, weaves, dyes, and handles fiber. Her passion is working from archaeological textile finds and re-creating historic textiles.

This article was published in the Winter 2014 issue of Spin Off.