Wool yarn
Wool yarn is the most widely used natural yarn for knitting and crochet — available in a wide range of weights, fiber types, and grades.
Types of wool yarn
Merino is the most popular wool yarn for its fine fiber diameter — typically 17 to 24 microns — which makes it soft enough to wear next to skin without irritation. It is well-suited to everyday garments, baby items, and anything worn directly against the body. Shetland wool is slightly coarser but exceptionally warm and has a traditional character that works well for colorwork and Fair Isle patterns. Bluefaced Leicester (BFL) has a silky lustre and smooth surface, making it good for lace and garments where drape matters. Corriedale is a sturdy, mid-grade wool that takes dye well and is forgiving for beginners. Icelandic wool has a distinctive dual-coat structure — an outer tog coat and a softer thel undercoat — that makes it very warm and rustic in character.
Yarn weights explained
Yarn weight describes how thick the yarn is. From thinnest to thickest: lace weight is extremely fine, used for delicate shawls and lace projects with small needles. Fingering or sock weight is thin but more workable, commonly used for socks, lightweight garments, and detailed colorwork. DK (double knitting) is a versatile mid-weight for garments and accessories. Worsted is the most widely used weight — suits sweaters, hats, and scarves. Aran is slightly heavier, good for cables and structured knitwear. Bulky and super bulky are thick, fast to knit, and best suited to outer layers and accessories where warmth rather than fine detail is the goal.
Ply vs weight
Ply is a common source of confusion. It refers to the number of individual strands twisted together to make a yarn — a 4-ply yarn has four strands — but it does not reliably indicate thickness. A 4-ply yarn from one manufacturer can be completely different in thickness from a 4-ply yarn from another, depending on how thick each strand is before plying. The number that actually matters is the recommended needle size listed on the label, or the wraps-per-inch count. When substituting yarn for a pattern, match by needle size and gauge rather than by ply number.
What to look for
Fiber content first: 100% wool performs differently from blends, and the breed matters for softness and durability. Check whether the yarn is superwash treated — if machine washability matters for the finished project, superwash is important. Certifications: RWS or ZQ for animal welfare, OEKO-TEX for dye safety. For hand-dyed yarns from indie dyers, asking about the base yarn source is worthwhile — many use certified bases even when they don't carry their own certification.
Superwash vs non-superwash
Superwash wool has been chemically treated to remove the microscopic scales that cause felting, making it safe to machine wash. It is more practical for garments that will be worn and laundered frequently, especially items for children. The tradeoff: the chemical treatment changes the surface of the fiber, and some knitters find superwash wool feels slightly different — sometimes more plastic-like — compared to untreated wool. Non-superwash wool requires more careful hand washing but is more natural in character and tends to pill less over time.
Common questions about wool yarn
What is the difference between wool yarn types?
The main differences are fiber diameter (which affects softness), fiber length, and breed characteristics. Merino is fine and soft — suitable for next-to-skin wear. Shetland is slightly coarser but very warm with excellent stitch definition for colorwork. Bluefaced Leicester has a silky lustre and good drape. Corriedale is sturdy and forgiving — a good all-purpose yarn. Icelandic wool has a dual coat structure that makes it exceptionally warm but more rustic. Each type suits different projects and different uses.
What does superwash wool mean?
Superwash wool has been chemically treated to remove or coat the microscopic scales on each wool fiber. Those scales cause felting — when agitated in hot water, they interlock and the fabric shrinks dramatically. Removing them makes the wool machine washable and prevents felting. The tradeoff: the chemical process (typically chlorination or polymer coating) alters the natural surface of the fiber, making the yarn feel slightly different and less "woolly." Some knitters prefer non-superwash for a more natural result; others value the machine-wash convenience.
Is wool yarn itchy?
It depends on the fiber diameter. Wool fibers thicker than around 30 microns can feel scratchy against sensitive skin. Fine wools like merino (typically 17-24 microns) are soft enough for most people to wear directly against skin without irritation. If you have found wool itchy in the past, look specifically for merino, merino blends, or other fine-fiber breeds rather than avoiding wool entirely. The variety labeled "lambswool" is also generally fine and soft.
What weight wool yarn is best for beginners?
Worsted or aran weight is easiest for beginners — thick enough to see stitches clearly, not so bulky that tension is hard to control. DK is also manageable. Avoid very fine yarns (lace, fingering) until you are comfortable with basic technique, as they are harder to see and correct. For fiber, a smooth worsted-weight merino or Corriedale is forgiving — the smooth surface shows stitch definition clearly, and slight imperfections in tension are less visible than in highly textured or novelty yarns.
What certifications should wool yarn have?
For animal welfare, look for RWS (Responsible Wool Standard) or ZQ Merino certification. Both verify humane treatment and responsible land management. ZQ is specific to merino. For dye safety and chemical processing, OEKO-TEX Standard 100 confirms no harmful substances in the finished yarn. GOTS (Global Organic Textile Standard) covers organic fiber through to the finished product. Many small indie dyers work with certified base yarns even when they do not carry certification on their own labels — asking the dyer about their base yarn sourcing is reasonable.
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