KDTV: Washing wool

posted in: Knitting, Spinning, Wool | 4

I still need to write the third post about the numbers in The Fleece & Fiber Sourcebook, but I'm prepping to teach at Madrona and it's all-consuming.

Yet here's a loooooong post that was published on the Knitting Daily TV site today. I'm taking the unusual step of presenting it here as well, because it involved a lot of work and because I want to alert my blog readers that if they go to the KDTV site and leave a comment by noon Central Time on Monday, February 13, they might win some Unicorn Fibre Wash, Unicorn Fibre Rinse, and Unicorn Power Scour.

I've just watched the KDTV video segment on cleaning wool, and considering that host Eunny Jang and I work entirely unscripted and that I wasn't able to get the specific background information I wanted from some sources in time for the taping, I think we did a pretty darn good job. (You may notice my slight discomfort in the situation because of the number of vocal pauses―um―in this segment. I need to learn to relax and trust that I do know enough about fibers to fill a five-minute spot on the spur of the moment, even when I didn't get the info I wanted!)

Anyway, this post contains useful information about cleaning wool. My study of the topic has come up with even more cool stuff that I'll need to write up another time.

I really like the Unicorn products. I'm not paid to say that—not paid here, not paid when I appear in the KDTV episodes that they sponsor, and not paid for the ad they've been running—although Unicorn has helped out with my research by sending me Power Scour to use once they figured out that I think it's great and am happy to say so.

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Washing wool

I love washing wool, whether it's fleece I'm going to spin, a newly finished garment whose beauty will be revealed after its first bath-and-blocking, or a loyal garment that has earned refreshment.

Freshly shorn wool may be the most fun to wash, because of its dramatic transformation. The grease that coats the fibers when the sheep is using the fleece to keep herself warm through the winter is still soft, resilient, and relatively easy to remove. I think of the animal, freshly released from this seasonally necessary burden to enjoy the spring air (and to begin growing next winter's blanket), and I think of the fabrics I will make from her hand-me-downs to keep other beings cosy in the future.

Even long-stored fleece can be rewarding to put through the washing process, which releases it from a stiff accompaniment of old grease and dust. Although it's best to wash wool soon after shearing, in part because moths especially savor the "extras" that are removed when the fiber is cleaned, as long as you can keep pests away you can safely store wool for many years.

Here's Emma's fleece when she was done with it, on its first trip into the warm water that begins my washing process:

LeicesterLongwool-firstrinse_7264
  • START OF CYCLE, when the wool has ONLY been soaked in warm water. The dark brown in the center tray is water soluble dirt and suint, formerly in the wool that's in the tray on the right. The wool in the tray on the left is still soaking.

It's easy to imagine that Emma would want to start over with fresh growth!

Emma is a Leicester Longwool sheep, a breed known for its long, shiny, strong fiber. The beauty of the wool becomes apparent after about two hours of soaking in a series of baths, beginning and ending with plain-water versions, and with two or three in the middle that are infused with a washing agent.

 

LeicesterLongwool-finalwash_7275

 

  • END OF CYCLE after use of washing aid. Again, the tray of wool on the right has been pulled out of the center tray, and the one on the left awaits draining. You'll notice some color variation still in the wool. It's all clean, however. This cycle consisted of (1) two plain-water rinses, (2) two soaks with washing aid, and (3) two plain-water rinses. Each bath was 20 minutes long, for a total of two hours of washing, although my active involvement only occurred at each transition point, removing the upper draining tray, changing the solution, and re-immersing the fiber. All water temperatures were standard-issue from the household system, which is not set to be exceptionally hot—about 135°F.

I've described the details of my washing process elsewhere. Today I want to talk briefly about the transition from dirty to clean, mostly for fleece but also for garments.

 

LeicesterLongwool-dirtyclean-7278

These are both Emma's wool, from the same shearing: as shorn (dirty) on the left and after its trip through my bathtub (clean) on the right.

Washing or scouring?

Washing is what I just talked about. The process of cleaning raw wool is also sometimes called scouring, a term used in industry to include the removal of all contaminants from wool―scouring is "washing plus."

What might the contaminants in wool be? I say might because not every fleece will have all of these, and each fleece will have contaminants in differing types and proportions.

The big three, present to some extent in every fleece, are:

  • wool wax or wool grease
  • suint
  • dirt

Wool wax or grease is not water-soluble. It provides a protective coating, and, in general, the finer the wool the more grease it contains. It's the hardest of the three main contaminants to remove. That's the point for the sheep! It shouldn't be easy to remove!

Suint (think "sweat") is water-soluble―even in cold water. When we're washing wool, it's the easiest contaminant to get rid of.

Dirt is soil, and can be dust or mud. It can be sandy, or full of clay, or may correspond to any of the gardener's or farmer's other options, and it can be easy or hard to remove, although most of it isn't too bad. (Clay, of course, is most difficult, as it seems to be for growing plants where I live.)

Vegetable matter (or VM) is another contaminant that comes in many varieties. For hand processing, VM isn't, for the most part, removed during the washing sequence and its evaluation and management is a topic for another day. In industrial processing, treatment to remove VM occurs during the scouring sequence and involves a delicate sequence of chemical and mechanical maneuvers to get the plant material out without damaging the wool―a different topic for another day (although I talk about it some in the KDTV segment).

Some other contaminants―like dung tags, urine stains, marker dye, and insects―should have been removed before the fleece ever reached the washing or scouring stage.

What to use as a washing aid?

For the intermediate steps of cleaning wool, whether raw or spun or made into fabric, we have many choices in washing aids. I've used a number of them over the years. At this point, I have several criteria for the agent that I use. Oddly, they all start with E!

I want it to be effective, efficient to use, economical, and as environmentally benign as possible.

That means that I look for a washing assistant that

  • is concentrated so I don't need to use large quantities
  • creates minimal suds (which are hard to rinse out, wasting both time and water)
  • does not subject the wool to significant and potentially damaging pH shifts
  • works at moderate heat levels even for fine wools (in order to reduce the potential of fiber damage, and so I don't have to be boiling water or otherwise wasting energy)
  • cleans by bonding with the waxy or greasy particles, drawing them off the fiber and into the water so they can be rinsed away, instead of being knocked off through agitation (which can result in unintended felt, as well as more work for me)
  • does not involve enzymes (which continue to be chemically active even after they've been discarded) and
  • contains no ingredients classified as toxic.

I now use washing agents that are specially formulated for use with wool.

Dishwashing detergents and shampoos create annoying amounts of suds. I'd rather avoid the perfumes and colorants that many cosmetic products contain—and they suds a lot, too. Laundry detergents often contain brighteners, enzymes, and other ingredients I consider extraneous at best and damaging at worst. Some components of laundry detergents are actually designed to break down proteins (to get out stains like blood or egg), and animal-source natural fibers are also proteins. It is interesting to check these products' Material Safety Data Sheets (MSDS) or, for some items, the information in the Household Products Database maintained by the U.S. Department of Health and Human Services ("Inside the Home" and "Personal Care" categories).

I wash all my natural animal fibers at between 50 and 60°C (120 and 140°F), preferably on the lower end. Wool wax, the stickiest contaminant to remove, melts at 35–40°C (95–104°F) and damage to protein fibers can occur at higher temperatures. The length of time that fiber is exposed to high temperatures, and the pH of the environment, matter a great deal. Dyeing fibers involves balancing these factors in exchange for a rainbow.

LeicesterLongwool-handspun_4067_2

Undyed handspun Leicester Longwool samples.

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A practical footnote and a random fact

Footnote
Here's a quick note about washing fine wools in their raw form: When wool wax is dissolved, its chemical composition changes. If the temperature of the bath cools, the grease can be redeposited on the fiber as a scum that can be substantially more difficult to remove than it was in its original form.

Random fact
Lanolin is produced from a portion of the wool grease recovered from scouring liquid.

Two excellent resources

Simpson, W. S., and G. H. Crawshaw. Wool: Science and Technology. Boca Raton, FL, and Cambridge, England: CRC Press Woodhead, 2002.

von Bergen, Werner. Wool Handbook: A Text and Reference Book for the Entire Wool Industry. 3d enl. ed. New York: Interscience Publishers, 1963.
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LeicesterLongwool-swatch-6588

Swatch knitted from yarn grown by Emma's Leicester Longwool flock mates, commercially spun.

For more on Leicester Longwool sheep, see "On the Edge: How a Handful of People Have Preserved Some Rare, Valuable Sheep and Their Wools," PieceWork, November/December 2011. Or, of course, The Fleece & Fiber Sourcebook. And Leicester Longwool will be one of the breeds I'm including in the Explore 4 retreat in Friday Harbor, Washington, in March! Yes, that's why I have been washing Emma's wool. We'll be working with it. (Curious? Download Explore-4_2012 PDF)

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4 Responses

  1. sergeantmajorette

    “…the grease can be redeposited on the fiber as a scum that can be substantially more difficult to remove than it was in its original form.”

    Oh, wow! Never thought about that, but it changes my thinking a LOT!

  2. Kate Larson

    Deb,
    Thanks for the great info, as usual! I am forever tweaking my washing process and love to hear about other people’s experiences.

  3. I’ve run into that ‘sticky glue’ – what a mess it is. Learned my lesson about not getting too distracted while soaking wool.
    I love your tray system. Is it designed for wool washing, or is it re-purposed?

  4. Now that I have the *proper* washing aid, the question becomes setting up a system that will let me wash about 30 llama fleeces without losing my purported sanity 🙂

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