Is Down Wool Resistant to Felting? Let’s Put It to the Test

We’ve all heard horror stories about woolen handknits being ruined by a trip through the washer and dryer. Fear of felting has driven the adoption of superwash wool as the yarn of choice for many knitters.

But I don’t love the way the superwash process changes the character of wool. And the chemicals involved in shrink proofing wool can be an environmental hazard.

I’ve often read that Down and Down-type wools are resistant to felting. That would be a boon for garments like socks, which can felt under the pressure of hot, sweaty feet, or for any project that will be used by someone who refuses to hand-wash. I decided to gather some samples of Down-type wools and put them to the test.

What are Down Wools?

The term “Down” in this context has nothing to do with soft, light, and fluffy. It refers to sheep breeds that were developed in the nineteenth century in the Downs of southern England. These are Southdown, Dorset Down, Hampshire, Oxford, Shropshire, and Suffolk sheep.

Breeds with different places of origin that grow fleece with similar characteristics are referred to as Down-type. These include (but are not limited to) American Tunis, California Red, Clun Forest, Polled Dorset, Montadale, and others.

In general, Down wools have a relatively short staple length of 2–4", with a fiber diameter in the range of 24–35 microns. Adult fleeces from true Down breeds is nearly always white.

Down breeds make up a large portion of the US sheep industry, yet finding breed-specific yarn from these sheep is a challenge. Down sheep are raised primarily for meat. Ranchers with large flocks typically sell their clip directly to wool mills, while the wool crop from smaller producers is often sold through wool pools.

What Yarns Did I Test?

For this test, I sourced one Down wool yarn and two Down-type yarns. Then I added a widely available Merino wool yarn as a “control.” Here are the specifics:

Yarn 1: Mountain Meadow Wool Suffolk – Semi Worsted
Fiber Content: 100% Suffolk wool grown on Surprise Co. Ranch, Kaycee, Wyoming
Put-up: 200 yds/100 g
Weight: Worsted
Swatch: Knit on size 7 (4.5 mm) needles
Color: Hand-dyed Marigold

Yarn 2: Solitude Wool Clun Forest Light
Fiber Content: 100% Clun Forest wool grown in Virginia and Maryland
Put-up: 240 yds/79 g
Weight: Sport
Swatch: Knit on size 6 (4 mm) needles
Color: Peepers and Wood Frogs

Yarn 3: Solitude Wool Dorset dress
Fiber Content: 90% Dorset wool, 10% nylon
Put-up: 268 yds/85 g
Weight: Laceweight
Swatch: Knit on size 2 (2.75 mm) needles
Color: Undyed White

Yarn 4: Cascade Yarns Merino DK
Fiber Content: 100% Merino wool
Put-up: 254 yds/100 g
Weight: DK
Swatch: Knit on size 6 (4 mm) needles
Color: #28 Harbor

The Process

I began by knitting a generously sized swatch with each yarn using the needle sizes recommended on the yarn labels. Without any sort of blocking, I measured the gauge of each swatch. For the photos, I pinned the swatches to a blocking mat just to stop them from curling up; I did not stretch the swatches.

The test swatches straight off the needles. Clockwise from top left: Suffolk, Clun Forest, Merino, Dorset. Photos by Sandi Rosner

I put the swatches together in a mesh laundry bag and washed them in my top-loading machine along with a couple of washable handknit sweaters. I set the machine for cold water and used the “delicate” cycle. I used a mild, plant-based laundry detergent. When the wash was done, I put the load in the dryer set for low heat and let them tumble for 20 minutes.

The swatches were still a little damp when they came out of the dryer, so I laid them out to finish drying overnight. Then I measured gauge and photographed the swatches again.

The test swatches after the first wash in cold water on the delicate cycle. Clockwise from top left: Suffolk, Clun Forest, Merino, Dorset. Photos by Sandi Rosner

For the second wash, the swatches were returned to the mesh bag and added to an average load of clothing. I used my usual settings on the washing machine: warm water and the “speed wash” cycle. This cycle includes more aggressive agitation and a faster spin rate. I set the dryer for medium heat and let it run for 30 minutes. Again, I measured and photographed the swatches.

The test swatches after the second wash in warm water on the speed wash cycle. Clockwise from top left: Suffolk, Clun Forest, Merino, Dorset. Photos by Sandi Rosner

The Results

All the swatches shrank lengthwise with the first wash, and the Merino exhibited a little more lengthwise shrinkage with the second wash. Surprisingly, three of the four swatches grew widthwise with the first wash. The Dorset Dress swatch shrank a bit in width.

I put my swatches through the second wash to see if harsher treatment (hotter water, more agitation, warmer dry) would result in more shrinkage. It did not. The Merino swatch went from 31 rows to 32 rows in 4", a difference of just 3%. The other swatches showed no change in gauge.

None of the swatches were completely felted, defined as the fibers becoming so enmeshed that the knitting can no longer be unraveled. But all the swatches showed visible changes after the two washes. The fabric was fuzzier. For both the Suffolk and the Merino, the swatches looked like they had been through a couple of years of hard wear, with some matting of the fibers and bunching of the fabric.

Conclusions

Remember, your mileage may vary. Washing machines differ. Additional trips through the washer and dryer may cause additional shrinkage, and even irreversible felting.

Down and Down-type wools may be slightly resistant to felting, but machine washing and drying still caused shrinkage. And none of my test swatches were improved by two trips through the laundry. The detergent, agitation, and temperature changes caused the swatches to look fuzzy and worn.

No matter what breed of wool you choose, your handknits will look better longer if you treat them with the loving respect they deserve. While a garment knit with a Down wool may not be ruined by an inadvertent trip through the washer, such treatment abuses the fibers. For most woolen garments, a gentle hand washing once or twice a year will keep them looking great for many seasons to come.

Sandi Rosner (she/her) learned to knit in the late 1970s from the instructions in the back of a magazine. She now works as a freelance designer, technical editor, writer, and teacher. When Sandi isn’t knitting, she usually has her nose in a book. Find more of Sandi’s work at www.sandirosner.substack.com.

** Header image: Courtesy of J gareth p, CC-SA 3 Unported