Super What Now?
Tech Talk: Wool, Part 2
August 26, 2024
Last week, we talked about sheep wool, including how to measure its quality and why we prefer Merino sheep wool for garments. Today, we’re talking about the difference between natural (untreated) and superwash wool. (Before we dive in, note that “natural” may also be used to describe undyed wool. For now, we’re only using this word to distinguish between how wool is treated to prevent shrinkage/felting.)
Have you ever machine washed something made from wool that shrunk (felted) so much you couldn’t easily see your stitches? If so, it was probably made with natural wool. To felt, natural wool needs heat (hot water), agitation (machine washing, usually) and soap. Sometimes, we machine wash natural wool on purpose, as in Suzy’s felted French Market Bag. However, many stitchers also have personal experience with accidental felting, as in Caryn’s Entrelac Shrug that shrunk from a generous adult size to a toddler size. (Want to see the difference in person? We have both the shrunken vest and an adult size in the shop!)
But many of us have machine washed wool items and they seemed just fine, so what’s the difference? These projects were likely made with superwash wool, which has been chemically treated to remove or coat some of the fiber’s outer layer. This layer is made of overlapping scales (like roof shingles) and removing or coating the scales makes it harder for the fibers to stick to each other. Superwash wool is generally (not always, check the maker’s label!) machine washable and it can feel softer than natural wool.
How do you choose between natural and superwash wool? First, are you concerned about long term care and durability? Machine washable yarns are great for gifts and high friction use, like socks. If you’re using colorwork techniques, natural yarn is a good choice, because the fiber will bloom nicely and attach to adjacent fibers. Also, natural wool is more sustainable, because making it uses less chemicals and creates less waste water than superwash wool.
Ball bands (labels) should tell you if the wool is natural or superwash and how to care for it. For example, Cascade Yarn’s Heritage is superwash Merino wool and machine wash, gentle. Sometimes the care instructions use symbols. If you need help deciphering them, the Craft Yarn Council explains them. Finally, if the ball band doesn’t specify washability, assume the wool is hand wash – better safe than sorry!
Caryn and the Yarnivore Crew
Coming Attractions!
P. S. Yarnivore will be open regular hours over Labor Day weekend.
P. P. S. There's still time to sign up for Denise's Knitting: Building in Color class, eleven 2-hour sessions on colorwork! And Suzy just added Knit & Felt a French Market Bag for Fall to the September calendar.
P. P. P. S. Mark your calendars for The Best Little Yarn Crawl in Texas, October 11 - 20, 2024. We'll announce when Passports are available for purchase. Early birds will get a Crawl bag!