If you read my previous post about superwash treated wool, you’ll know that wool is a many-scaled thing. While I didn’t dive too deeply into the subject, the TL;DR version is this:
Individual wool fibers are made up of scales that expand under heat and agitation; these scales then hook onto each other and become enmeshed, creating the phenomenon we know as “felting.” Superwash is treated with chemicals to smooth out these scales and prevent the felting process. The chemicals are not typically eco-friendly.
NSW (Safe for work, I assure you)
Non-superwash wool, or NSW, is a little different. As straight-from-the-fleece as a biggish operating mill can claim (we’re not talking farm-to-table, but maybe farm-to-grocery-store-to-table?), this wool is untreated, and its scales are still intact. But, how big are the scales? That's for the micron count to tell us: Fine wool will have a smaller micron measurement, and with a smaller micron measurement, the surface area of the wool and the scales themselves will be smaller. This means less immediate felting than coarser wool. It doesn't mean no felting potential, but it means felting less quickly. This is at least from my (limited) experience dyeing different wools; I mostly dye fine grade NSW.
The fineness of wool can be determined by many factors, such as breed and age. That's a Whole Other Thing, and we won't be covering too much of that here--mostly because I don't know much more than that statement. I can say, however, that this is why Merino sheep are such an industry standard: Their wool tends to lean toward the fine grade. Microns, a microscopic measurement, are employed to determine the fineness of a fiber by measuring their individual diameter. The lower the micron, the softer it will be. It ranges from Very Coarse (>40-36 microns), Coarse (35-31 microns), Medium (30-22 microns), and finally, Fine (21-17.5 microns). Typically, dyers carry "Fine" merino, or even "Superfine" (which is probably <17.5 mircons).
Microns apply to both NSW and SW wools, as it is a measurement of the diameter of the individual wool fiber itself. More often than not, we expect SW wool to be softer than NSW, often because of two things: the coating of the SW fibers and our concept of what "natural" yarn should feel like. When you have a non-merino wool, you'll probably have a higher micron count than the common "fine merino" grades, and it will feel more "wooly." Different breeds of sheep will have different properties to their wool on top of micron count, so it's always fun to try breed-specific yarn!
What dyeing NSW means for most dyers
When we dye wool yarn, we need heat and acid to set the dyes. So what happens when we dye yarn that’s non-superwash? For starters, we need to adjust our timing and technique. This yarn needs to go into the pot at room temperature to avoid shocking the fibers into suddenly expanding (because heat), and dyeing itself needs to be as low agitation as possible. That’s difficult if you’re glazing and layering colors like I do and constantly moving the yarn around to ensure an even coating of dye. After it’s dyed, it’s recommended to leave in the pot and let it come back down to room temperature.
If you’re a small operation like me, that means that I’m down a pot for the rest of the day. It’s doable, by all means—in fact, I often plan these NSW yarn dyes for end-of-the-day dye sessions to let them sit overnight—but it does indeed add to production time and cuts down on my general production capabilities if that's the majority of what I'm dyeing. Dyeing only NSW-treated yarns takes a very special person with very special patience. I am not that person. 🙃
I use this title on my website to describe what colors present as on a NSW base. Watercolors aren’t all pastels; you can get some very beautiful, vibrant, deep hues from them, but they are still watercolors. Colors on superwash yarn will present much more like oil paints that can be layered and mixed and applied precisely. When I speckle NSW yarn, the speckles produced—regardless of how much citric acid I use—always present as concentrated watercolor droplets. They are still concentrations of color, but they are far less vibrant and precise as their SW counterparts, spreading out and taking a little more space before they set.
For this reason, I don’t offer all of my speckles on NSW yarn. Sometimes a colorway just doesn’t speckle well on untreated yarn, bleeding into each other and becoming muddy.
Should all of my yarns be family-friendly? 100%. But for those of us who have chronic health issues and increased sensitivity or even hypersensitivity, sometimes our bodies pick up on treated wools and react to those treatments. When someone isn't hypersensitive to these chemicals, it's a bit hard to imagine that something they personally don't feel could be felt by someone else, but that's health for you! We are all so very individual. Untreated wools are typically free of those chemicals and are generally safe even for the most sensitive of us--those who are new to the world.
Some of my NSW bases are GOTS-certified organic, which means they really are what they say they are: sustainably raised, no added harsh chemicals. While I don't think that you would be knitting a camel and silk romper for a little one (😂 what a little diva!), I generally am referring to my organic and NSW sheep wools here.