Lately I have been so inspired to knit with natural wool yarn and bamboo needles. There is something grounding about it. Natural fibers in my hands, warm wooden needles, and a fabric that feels earthy and alive. And then there is my favorite moment of all: when a finished piece comes out of its bath and wet blocks into a soft, drapey fabric that feels completely different from the one I cast off.
I wanted to understand why this pairing feels so good, so I dug into the fiber science. Here is what I learned about lanolin, why some wool is itchy and some is not, what makes merino wool special, how wet blocking actually works, and why so many knitters love bamboo knitting needles.
What Is Lanolin in Wool Yarn?
Lanolin is a wax secreted by the sebaceous glands of wool-bearing animals. You may also see it called wool wax, wool fat, or wool grease. On the sheep it has a practical job: its waterproofing property helps sheep shed water from their coats.
There is a surprising amount of it on a fresh fleece. Crude lanolin makes up roughly 5 to 25 percent of the weight of freshly shorn wool. Before wool is spun for most commercial uses it is scoured, which means washed in hot water with a special wool-scouring detergent, and the lanolin that is removed goes on to be used in products like cosmetics.
Not every yarn is scoured the same way, though. In less-processed wools, some of the lanolin can be left intact by using gentler detergents. This kind of semigrease wool can be knit into water-resistant mittens and sweaters, which is a lovely nod to what lanolin does for the sheep in the first place.
Why Some Wool Feels Scratchy (and Some Doesn't)
If you have ever wondered why one skein feels like a cloud and another makes your neck tingle, the answer is mostly about fiber diameter, measured in microns (micrometres). Fiber diameter is considered the single most important characteristic in determining wool quality and price.
That itchy, prickly feeling is not usually an allergy. Research shows that wool itself is not an allergen. Instead, itch and prickle happen when coarse fibers thicker than about 30 to 32 microns press or brush against the skin. Very fine fibers behave differently: superfine and ultrafine merino bend easily against the skin rather than poking into it, which is why fine wool can feel so gentle.
Fiber diameter also varies more than you might expect. One study comparing three sheep breeds found average diameters ranging from about 27.7 microns in the finest breed to about 39.6 microns in the coarsest, and it found that the body region the wool came from had a significant effect on diameter too.
So what is the secret to soft wool that isn't itchy?
- Look for fine fibers. Fibers finer than the 30 to 32 micron range are less likely to prickle.
- For sensitive skin, go finer still. Superfine and ultrafine merino under 18.5 microns may be more comfortable for sensitive skin.
- Give it a bath. Gentle washing helps wool soften and bloom, though it will not turn a rustic wool into cashmere. More on that below.
Merino Wool vs Other Wools
Merino wool is known for its fineness. Merino fibers typically measure between 12 and 24 microns, and the finest and most valuable wool comes from merino sheep. Merino is also graded by how fine it is:
- Ultrafine merino: up to 15.5 microns
- Superfine merino: 15.6 to 18.5 microns
- Fine merino: 18.6 to 20 microns
- Medium merino: 20.1 to 23 microns
- Strong merino: 23 to 25 microns
Compare that with the breed study above, where even the finest of the three breeds averaged nearly 28 microns. That gap is a big part of why merino feels so different next to the skin.
The Natural Properties of Wool
Part of what makes a natural fiber yarn like wool feel so comforting is how it works with your body.
- Warmth: Wool has a natural wave, or crimp, that traps pockets of still air, insulating your skin from the cold.
- Breathability: Wool fibers are naturally breathable. They can absorb large amounts of moisture vapour and allow it to evaporate.
- Moisture: Wool can absorb up to 35 percent of its weight before it feels wet and clings to the skin. As it absorbs moisture, wool releases heat, which helps you feel warmer and drier in cold, damp weather.
- Water resistance: The surface of the fiber is covered in tiny overlapping scales, all pointing in the same direction, which helps liquid roll off.
How Wet Blocking Works on Wool
Wet blocking is the step that turns a just-finished piece into a finished garment, and with wool it can feel like magic. Here is what is happening. When wool gets wet, the natural hydrogen bonds in the fiber begin to break, making it more malleable. As it dries, new bonds form, so the piece dries into the shape you gave it, until it gets wet again. Blocking straightens the stitches and evens out the tension.
Wool also blooms. After a soak, the fiber relaxes and fluffs up a little, and the stitches may fill in. That is the soft, drapey transformation I love so much.
How I wet block a wool knit
- Fill a basin with lukewarm (tepid) water and add a few drops of wool wash.
- Submerge the knit fully, without agitating it, and let it soak for about 15 to 30 minutes depending on its thickness.
- Lift it out supported from underneath so the weight of the water does not stretch it.
- Gently squeeze out the water. Do not wring. Roll it in a dry towel and press to remove more.
- Lay it flat, smooth or pin it to the measurements you want, and leave it until completely dry. Hanging a wet knit can stretch it permanently.
Why so gentle? Felting happens when heat, motion, and moisture cause the scales on wool fibers to open and then latch onto each other. A calm, still soak gives you all the softness of blocking without that risk.
Why Knitters Love Bamboo Knitting Needles
And then there are my needles. Bamboo knitting needles have a natural, earthy feel, and they warm slightly to the touch, while metal needles tend to feel quite cold. A few more reasons knitters reach for them:
- Less slippery: Bamboo starts out with a little friction, so stitches are less likely to slide off. That makes it a comfortable choice for beginners and for slippery yarns.
- Lightweight: Bamboo is lighter than traditional wooden needles, and metal needles are heavier still.
- Quiet: Metal needles can make a clinking sound, while bamboo is much quieter and more soothing.
- Strong and flexible: Bamboo is difficult to break, though needles can develop a slight curve over time.
The trade-off is speed. Metal needles are smooth and fast, which many experienced knitters prefer, while bamboo becomes smoother and faster with use. For slow, mindful evenings with natural wool yarn, I think bamboo is a perfect match.
If you are new to any of the terms here, our Knitting Dictionary is a great place to start, and our Help page has answers to common questions.
Frequently Asked Questions
Is merino wool itchy?
Merino is much less likely to itch than coarse wool because its fibers are fine, typically 12 to 24 microns. Itch and prickle are linked to fibers thicker than about 30 to 32 microns, and superfine merino under 18.5 microns may be more comfortable for sensitive skin.
What is lanolin in wool yarn?
Lanolin, also called wool wax or wool grease, is a natural wax produced by sheep that helps their coats shed water. Most of it is washed out during scouring, but gently processed yarns can keep some of it, which adds water resistance.
Does wet blocking make wool softer?
Gentle washing helps wool soften and bloom, and blocking evens out your stitches. It will not change the fiber itself, though, so a coarse wool will still feel rustic.
Are bamboo knitting needles good for beginners?
Yes. Bamboo has a bit of friction, so stitches are less likely to slide off the needle. It is also lightweight, quiet, and warm in the hand.