By Claudia Ostrop
We all know some wool feels as soft as a cloud, while others are rough and scratchy. The answer lies in the micron values of the fibers used, which determine their thickness and texture. But what exactly does "micron" mean, and is a higher or lower value better? Let's explore!
Micron – What’s Behind This Mysterious Number?
The feel of a yarn is closely tied to the properties of the fibers it is spun from. Whether we perceive a yarn as soft or scratchy is determined by the fiber thickness, which is measured in microns.
Micron values are a critical indicator of fiber quality, as they directly affect the texture, durability, and of course, the general feel and haptics of the finished yarn. Naturally, fiber length and structure, and not least the spinning process, also play a decisive role in the overall quality of the finished yarn – but the feel on the skin is primarily determined by fiber thickness. Lower micron values indicate finer fibers, while higher values correspond to coarser fibers.
What Exactly is a Micron?
Now, let’s get a bit technical: A micron, short for micrometer (abbreviated "µm"), is a unit of measurement equal to one-millionth of a meter. Or put another way: 1,000 microns equal 1 millimeter (which is approximately 0.039 inches)
In this context, the micron value indicates the diameter of a single fiber, i.e., how thick (or rather: how thin) it is. This is crucial when it comes to the quality, comfort, and durability of a yarn.
For example: Fibers with a diameter of 15 microns are ultra-fine and feel incredibly soft. Fibers with 40 microns? More suitable for robust carpets.
In short: The lower the micron value, the finer the fiber – and the more luxurious the yarn. For comparison: Human hair has a thickness of 50 to 150 microns.
How Are Micron Values Measured?
As mentioned earlier: A micron equals one-millionth of a meter. That’s too small for rulers or measuring tapes. Therefore, advanced measurement techniques are needed to precisely determine fiber thickness.
Laser Microscopy
This is a highly accurate technique used to measure the diameter of individual fibers. In this method, a specialized microscope equipped with laser technology is used to scan the fibers. The laser beams precisely detect the fiber's thickness by analyzing the interaction of the light with the fiber's surface. This allows for precise and reliable measurements of even the thinnest fibers.
OFDA (Optical Fiber Diameter Analysis)
The "optical fiber diameter analysis" uses state-of-the-art imaging techniques to capture high-resolution images of the fibers, which are then processed using specialized software to calculate their average diameter.
Airflow Measurement
Airflow measurement involves measuring the resistance that the fibers create as air is forced through. Fibers with smaller diameters will allow more air to pass through with less resistance, while thicker fibers will block more air, resulting in higher resistance. By analyzing this resistance, the average diameter of the fibers can be calculated indirectly. (Picture: Paul examining fibers)
How Fiber Thickness Influences Yarn Properties
Micron values have a significant impact on (almost) everything you love about yarns:
How they feel to the touch, how they knit up, and how they feel on your skin.
Fine Fibers Feel Softer on the Skin
The finer, the thinner a fiber – i.e., the lower its micron value – the more flexible it is. It’s logical, isn’t it? A yarn made from very fine fibers feels soft because it is wonderfully pliable. In contrast, a yarn made from relatively thick fibers is stiffer and less supple.
The flexibility and elasticity of fine fibers are precisely why some yarns feel great against the skin, while others are not just perceived as scratchy—they truly are!
While personal sensitivity plays a role, yarns with very low micron values generally feel soft and comfortable on the skin. The reason is simple: The fibers are so soft and flexible that they don’t irritate or prick the skin. They simply yield and bend away upon contact with the skin, avoiding irritation or discomfort.
On the other hand, thicker fibers are less flexible within the thread and the knitted fabric. When such fibers come into contact with the skin, they don’t bend as easily, resulting in slight irritation. Depending on your sensitivity, this might feel like a mild tingling or even a scratchy sensation.
By choosing fibers with lower micron values, you can enjoy yarns that are as gentle on the skin as they are beautiful to work with. (Picture: Vicuna fiber)
Strong Fibers Last Longer and Endure More
Even though we tend to favor soft wool and yarns, stronger fibers certainly have their merits: In terms of durability, they outperform their delicate counterparts.
For projects that need to be more hard-wearing, coarser fibers with higher micron values are ideal. The best examples are socks or a cardigan "to throw on." Incidentally, you’ll often find that robust yarns don’t specify micron values – these are generally only given when fiber fineness is emphasized or particularly highlighted. (Picture: Alpaca fiber)
Micron Values Compared: How About Something Softer?
To get more specific, here’s an overview of where the micron values of different fibers typically fall:
Fine Fibers: The Who’s Who of Yarn Royalty
Vicuña
Never heard of vicuña? Then it’s about time! Vicuñas live in the highlands of South America and belong to the camel family. With micron values between 8 and 13, it is the finest and rarest natural fiber in the world. Incidentally, we are among the few suppliers of hand-knitting yarn made from vicuña wool!
Cashmere
Cashmere is widely regarded as the epitome of luxury in both the knitting and fashion worlds—and for good reason! Renowned for its unparalleled softness, cashmere fibers range between 14 and 19 microns, making it exceptionally gentle on the skin, whether you’re knitting or wearing it. Our cashmere collection features cashmere in its purest form as well as in carefully developed blends, offering a touch of elegance for every project.
Merino
Merino is the ultimate all-rounder! The superfine variety, with fibers under 18 microns, is perfect for creating soft, warm garments like sweaters, scarves, shawls, and hats. It's even ideal for the littlest ones, offering unparalleled comfort.
However, not all merino yarns are created equal—some can be quite rustic! The coarseness of the fibers can vary significantly depending on the origin of the sheep (for example, those from cooler climates tend to produce coarser fibers).
Our merino collection features a wide range of luxuriously soft merino options, including pure superfine merino and beautifull blends with other fibers, ensuring there’s something for every project.
Alpaca
Alpaca fibers come in a wide range of thicknesses, but baby alpaca stands out for its incredible softness and luxurious feel. With a fiber thickness of up to 22 microns, baby alpaca is wonderfully gentle and cuddly. Fibers thicker than this can sometimes feel prickly, but baby alpaca remains smooth and comfortable, making it ideal for clothing and accessories.
Not only is baby alpaca wool exceptionally soft, but it also retains its shape beautifully over time, ensuring your creations stay as stunning as the day they were made. Our alpaca collection features a variety of high-quality options made with or from pure baby alpaca wool, perfect for your next project.
Fine Micron Values and Their Role in Premium Hand-Knitting Yarns
When you knit, you want a yarn that feels amazing, is enjoyable to work with, and ensures your finished project not only looks beautiful but feels great to wear.
Knitting a piece like a sweater requires a lot of time and effort, so it’s worth choosing a high-quality yarn to avoid ending up with a scratchy, uncomfortable result. After all, your hard work deserves the best materials!
For projects like socks, runners, or baby blankets, however, durability often takes priority. In these cases, the softness of fine cashmere might not be ideal, as it can come at the expense of strength and resilience.
That’s why it’s essential to consider the purpose of your project and the wear and tear it might face. Selecting the right yarn for the job ensures your creation will not only be beautiful but also long-lasting and practical for its intended use.
The Micron: Small Yet Mighty!
Whether you’re new to knitting or have been knitting for years, understanding micron values is key to avoiding unexpected disappointments. As you now know, not all wool is created equal—merino isn’t always super soft, and even alpaca can sometimes feel scratchy.
When the micron value is given, it offers a clear and valuable indicator of the yarn's softness and quality. But even if it doesn’t, we hope this guide has given you the knowledge to read yarn labels more confidently and make choices that suit your projects.
After all, your knitting should be as enjoyable to wear as it is to create.
