The Ultimate Softness: Exploring the World of Merino Wool “Grades”

Merino wool is highly useful throughout the year, regardless of the season. But have you ever wondered why the price of merino wool differs from store to store? In fact, even among merino wool, there are different grades, and the price varies depending on “fiber fineness” and “color.” In this article, we will take a closer look at the grades of merino wool.

About Merino Wool Grades

Merino wool is classified into different grades according to the fineness of its fibers. The smaller the number, the finer the fiber; the larger the number, the thicker the fiber. Finer fibers are harvested in smaller quantities, making them rarer and more luxurious. In general, wool fibers finer than 19μm are considered high-grade wool and tend to be more expensive. This is because finer fibers are more difficult to process, and the required machinery and technical expertise are reflected in the price.

Fiber fineness is expressed in the unit “μm（micrometer）.” One micrometer is equal to one-thousandth of a millimeter.

During the combing process, wool is separated into longer and shorter fibers. In general, longer fibers tend to be finer, while shorter fibers tend to be thicker.

Finer fibers usually have a longer fiber length（the length of the fibers used to make yarn）and a softer feel, making them more comfortable against the skin. Shorter fibers, on the other hand, may feel stiff or rough, and are more likely to cause a prickly sensation.

In addition, finer fibers tend to have smoother cuticles, giving them a superior sheen and luster. Thicker and shorter fibers often have more unevenness and less luster.

About Fiber Color

The price of merino wool also varies depending on the color of the fiber. Raw wool that is closer to pure white tends to be more expensive, while wool closer to gray or brown is generally less expensive. Whiter fibers contain fewer impurities, and because they cannot be easily mixed with other shades, the amount that can be harvested is limited. This makes them more likely to command a higher price.

About the Super ○○'s Label

When it comes to woven fabrics such as coats or suiting materials, you may see what is known as the “Super” grading system. Some people may have seen labels such as Super100's before. The Super grading system increases in increments of 10, such as Super100's, Super110's, and Super120's. As the number becomes higher, the “raw wool fiber” becomes finer. Please note that this does not mean the “yarn” itself becomes finer.

The relationship between the Super grading system and μm is shown below.

The Difference from Yarn Count

Yarn count is a unit that indicates the fineness（or thickness）of yarn. It is a different measurement from the Super ○○'s system mentioned above. Yarn count is based on how many meters of yarn can be spun from 1,000g of cotton. For example, a 120-count yarn means that 1,000g of cotton can be spun into 120,000 meters of yarn.

As the length of yarn produced from the same weight increases, the yarn count number also increases. Therefore, the higher the yarn count, the finer the yarn is considered to be.

To summarize the difference between yarn count and the Super grading system: yarn count refers to the fineness of the yarn, while the Super grading system refers to the fineness of the fiber.

Incidentally, SUPER 150’S yarn is not necessarily finer than SUPER 100’S yarn. This is because yarn is made by bundling fibers together. Even if the fibers themselves are fine, the yarn can become thicker when spun. As a result, yarn made from SUPER 100’S fibers may sometimes be finer than yarn made from SUPER 150’S fibers.

Be Careful: The Same Super ○○'s Label Does Not Always Mean the Same Quality

For example, even if there are two products labeled Super100's, their prices may differ. This is because the same Super100's label does not necessarily mean the same quality. The reason is that wool quality varies depending on each individual sheep and the environment in which it was raised.

For example, the quality of wool from sheep carefully raised one by one can be completely different from that of sheep raised uniformly in large numbers. Wool quality can also vary from one individual sheep to another due to genetic factors. It is similar to how human hair quality differs depending on daily care and inherited traits from one’s parents.

The Super ○○'s label is simply a unit that indicates fiber fineness, so the quality of the final product ultimately depends on the natural potential of the sheep itself.

In addition, even if not all the fibers that make up the fabric are Super100's, the product may still be labeled as Super100's. If all the fibers used are Super100's, the price will be higher. If only part of the fibers are Super100's, the price will be lower.

For these reasons, even products with the same Super100's label may differ in price.

A Higher Super ○○'s Number Does Not Always Mean Better Quality

It may be tempting to think that “Super150's must be better than Super100's,” or that “a higher number is better” and “finer fibers are always better.” However, this is not necessarily true. There are several factors to evaluate, such as the quality of the raw wool, the fineness of the fiber, and the fineness of the yarn. In addition, the most suitable fiber depends on the purpose of the garment.

Merino wool becomes rarer and more luxurious when the fibers are finer and whiter, because less of it can be harvested. However, this does not necessarily mean that it is suitable for the garment you want to wear. Its higher value comes from rarity, and it does not guarantee the quality of the final product. For T-shirts or suits that are worn frequently in daily life, Super150's fibers may actually be too fine.

In short, the definition of quality as a fiber and the definition of quality as a finished product are not the same. That is why it is better to choose products by considering the balance of many different factors.