Generally speaking, worsted wool is the most popular fabric for men’s suits around the world and while there are technically many fabrics that fall into the definition of worsted, there are subtle differences in classification among them. One of these determining factors is the wool’s so-called super number. You may be familiar with seeing terms like super 120's or super 180's on online retail pages or in fabric swatch books but what exactly does the term super mean in relation to worsted wool?
What Qualifies As Worsted Wool?
The term worsted can alternately describe either a combed yarn, a fabric made from a combed yarn, or a weight of yarn. A combed yarn, by the way, is made when wool fibers are rotated by metal combs that align the long fibers while discarding these short staple fibers. The result is a long lasting fine and smooth yarn with a somewhat glossy finish. Also, by adjusting the pull of these combs on the wool, one can get lighter or heavier yarns whereas varying the twists will impact the look, feel, and strength of the yarn. Tight twisting provides a crisper feel whereas loose twisting makes for a softer but weaker yarn.
Is A Lighter Worsted Wool Better Than A Heavier Weight?
The answer is not necessarily, no. Let’s take an overcoat as an example of this principle; while a softer fabric would feel more pleasant on one’s skin, a heavier coat made of something like Donegal tweed is going to be much more sturdy and keep you warmer than a lighter and softer cashmere coat would. Of course, you’re not often going to be wearing an overcoat against your bare skin but this illustrates the principle that the heavier weight is going to be sturdier than the lighter weight even if the lighter weight is softer.
Similarly, you might be under the impression that a lighter weight weave is going to be cooler to wear and a heavier weight would be warmer but this isn’t always the case either. Something that’s heavy but relatively open in its weave like a fresco fabric, for instance, is going to feel much cooler when worn than something that’s tightly woven and lighter like a super 150's fabric, for instance.
With all that said though, fabrics commonly available today are just going to be lighter in general than fabrics which were produced 30 or 40 years ago or even more. This will be readily apparent to you if you visit a thrift store and pick out an old suit. It’s probably just going to be heavier than something you’d buy today. It’s important to keep in mind then that a lighter fabric with a higher super number is not a hallmark of better fabric, it just indicates the fibers used were thinner in diameter. Similarly, the super number doesn’t provide any information about the weave or how heavy the fabric is.
You might be surprised to learn that the wool used to manufacture a great many suits globally comes from sheep which are descended from just two rams and four ewes. In 1789, King Charles the fourth of Spain gifted six sheep to the Dutch East India Company; these sheep were then shipped to South Africa. In 1795, a British immigrant to Australia named John McArthur bought 26 of the offspring of these original six sheep and transported them back to botany bay. These 26 sheep were then bred to form the backbone of what’s now the Australian wool industry which has sheep that now number more than one hundred and twenty million. The wool from these sheep produced in grades between 60's and 80's around this time, essentially measuring how fine the yarns were, was top of the line. As such, most of it went directly to tailors on Savile Row. 100's grade wool meanwhile was thought to be unattainable at this time in history.
Until the wool mill of Joseph Lumbs and Sons in Huddersfield West Yorkshire England was finally able to produce some of it. Lumb bought enough of this wool for an entire year’s supply and brought it to market under the term Lumb’s Huddersfield super 100's thus super terminology for worsted wool suits was born. At this time in the late 18th century, British wool merchants would often refer to their wares by largely subjective terminology in describing how fine the wool was; terms like low, medium, fine, the newly created super, and so on. But because producers and consumers eventually wanted terminology that was more objective in how the wool was rated, the city of Bradford, England led the way in grading wool more objectively. This process became known as the English worsted yarn count system or more generally, the Bradford system. Fast forward now to 1968 when the USDA created the United States standards for grade wool, this assigned ranges of average fiber diameter or AFD and maximum standard deviation to the previously set up Bradford count.
So with these standardization systems in place, super still sits as the top designation for how fine wool may be. With that said, some companies have gotten a little subjective again in exactly how they’re grading their super wools. So for example, a super 200's wool from one manufacturer might be a bit different in how fine it is from a super 200's wool from another manufacturer. Things are generally going to be fairly consistent, overall. When we’re discussing reputable manufacturers of high quality, most of them are going to abide by the guidelines set out in the fabric labeling code of practice from the International Wool Textile Organization or IWTO.
So to recap then, what the super number is actually measuring is how fine the wool is because what’s being measured is how many times each of the individual woolen yarns have been twisted around. Generally then, the higher the super number is, the finer the cloth in question will be. Often, this means it will also be lighter but as we said earlier, this isn’t always the case. How fine these woolen yarns are is typically measured in micrometers also called microns.
So a higher super number will mean that a fabric is going to be softer to the touch and generally will feel more like luxurious. Conversely, a lower super number will mean that the cloth is more sturdy and probably warmer. As we’ve said, it will generally be heavier but not always. While it’s commonly believed that the super number of a given fabric also has something to do with its individual thread count, this simply isn’t true and there’s not a correlation between the two measurements. While a higher super number does to some extent denote the exclusivity of a given fabric, because something like a super 200's would contain some of the rarest wool fibers available, this is only an indication of that exclusivity and rarity, not necessarily subjective quality.
Here’s another important note, the full word “super” can only be applied to fabrics made of pure new wool. Also, fabrics made with wool blended with other things like cashmere, alpaca, silk, or so on can use the slightly related S designation, though not the full word super.
Super “S” Number Maximum Fibre Diameter
SUPER 80’s 19.75 µ
SUPER 90’s 19.25 µ
SUPER 100’s 18.75 µ
SUPER 110’s 18.25 µ
SUPER 120’s 17.75 µ
SUPER 130’s 17.25 µ
SUPER 140’s 16.75 µ
SUPER 150’s 16.25 µ
SUPER 160’s 15.75 µ
SUPER 170’s 15.25 µ
SUPER 180’s 14.75 µ
SUPER 190’s 14.25 µ
SUPER 200’s 13.75 µ
SUPER 210’s 13.25 µ
SUPER 220’s 12.75 µ
SUPER 230’s 12.25 µ
SUPER 240’s 11.75 µ
SUPER 250’s 11.25 µ
For standard everyday wear, you could go with something with a pretty low super number. Something that’s below 100 up to a super 100's or super 120's, for example. For an important business meeting, a conference, or something that’s a bit more important than the average day-to-day at the office, you could go with something like a super 130's or super 150's and for special events, you could go with something like a super 180's or anything above that. Again, these are just hypothetical suggestions.
If you really do want to pay attention to your super number, of course, you could wear a suit made from a different material entirely than worsted wool and still look good or you could wear a worsted suit that doesn’t even have a registered super number. You just have to make sure that the suit is fitting you well and flattering your form.
CONCLUSION
In conclusion then, while the super number of a worsted wool can be handy in determining how fine and soft the yarns of a given wool are, it shouldn’t be used as the only measure of quality in wool suiting. Remember to focus first on fit then determine if you really like the look of the suit and how often you think you will wear it. From this point, you can consider the super number.