This page is dedicated to wool as it relates to men’s suiting. If you’d like to learn more about other suit fabrics, see our fabric guide. In this guide, we will go over various elements of wool, and you can click any of the following links to jump to the section that most interests you:
- The Benefits Of Wool
- The Super Numbers & What They Mean
- How Wool Is Made
- Wool Cloth Weight Explained & Weight Guide
The Wool Suit
Wool is far and away the most common fabric for suits, and some of the most common and best wool comes from merino sheep in Australia. Wool is great because it:
- Breathes easily: Wool is woven and has air pockets and gaps throughout that you can’t see. The air pockets trap warmth while the gaps allow air to move through and thus let moisture evaporate.
- Is durable: When properly stored, wool will keep for decades.
- Is naturally water resistant. Sheep’s coats have a natural water-repellent fat called lanolin. While most of this is removed during processing, wool is still more difficult to soak than cotton. In addition, wool is hydrophillic; it can absorb up to 30% of its weight in moisture without feeling wet to the touch! Cotton, by contrast, can absorb up to about 8%.
- Has memory: Also known as “elastic recovery,” wool has a springiness that makes for good wrinkle resistance.
- Dyes easily: Wool suits are available in any color under the sun.
- Is naturally flame-resistant: You can never be too careful.
Lightweight wools are suitable for tropical climates, whereas heavyweight wools work beautifully to keep out a winter chill. More on wool weight can be found below.
Wool is generally found in two varieties: woolen and worsted. The difference is in weight and size of yarn, how fiber is prepared before spinning, and finally how the yarn is spun.
Woolens are scratchy and quite literally hairy. Think of how a Harris tweed jacket or lambswool sweater feels. These are classic, typical woolens. How does this occur?
Any given fleece will have fibers of varying lengths. Woolens are garments in which the individual fibers of varying lengths are not separated from each other. They go in various directions, overlap each other, and create numerous air pockets between the individual fibers.
Worsted Wool: What Is It?
We hear the term “worsted wool” often when we’re shopping for suits, but what does it refer to?
Worsteds are smooth and soft. This is because the individual fibers are roughly the same (long) length and run parallel to each other. Little to no space is left between the fibers and you get a soft, lustrous feel. This is the finished product after the process of combing a fleece and separating out the short fibers. The remaining long fibers are lustrous and have a soft feel to them.
You might be thinking, “Well, all my suits feel just like that,” and you would probably be right. The lion’s share of men’s suits, especially on the ready-to-wear market, are made of worsted wool.
Worsted can be either combed or carded. Combed worsted are achieved by rotating metal combs that align the long wool fibers in parallel while separating out the short staple fibers. This gives you the smooth finish you’re accustomed to. Carded yarns, on the other hand, are brushed in a way that retains all the fibers, regardless of their length. The finish is fuzzier and more matte than combed yarns.
Note that worsted also refers to a type of weave, which is covered in our general fabric guide.
Super Numbers: How Wool Is Classified
Anyone who’s been to a menswear shop has likely seen terms like “Super 120’s wool” or something of that nature. Many salespeople erroneously tell their clients that it’s the wool’s thread count. This is completely false. Thread count is for cotton, not for wool.
A simple explanation is that a wool’s “super” number is an indicator of fineness. The higher the number, the finer the wool, and vice-versa. This is a perfectly accurate way to think about super numbers, and it will inform your purchases well enough.
A more in-depth, explanation, however, is also warranted. To do this, we need to define a “hank:” a spool totaling 560 yards of yarn that can be spun from a pound of raw wool.
The Super number simply indicates the number of hanks that can be spun from a pound of raw wool. Super 100’s wool means that 100 hanks can be spun from the raw product. You can get 150 hanks from Super 150’s, 80 from Super 80’s, and so on. The finer the fibers, the more hanks can be spun, and the “high super number means a finer fabric” rule still holds.
In much the same way of off-the-rack clothing sizes, there’s no international standardization for this. One company’s Super 200 can feel rougher than another’s Super 150. Furthermore, a wool’s “S” classification has nothing to do with its weight or quality indicators such as length or strength of fibers.
How To Measure Wool Fibers
One measurement you’ll rarely hear of outside of custom clothing circles is what’s called a micron.
An individual fiber is measured in micrometers, commonly referred to as “microns” (μm), or one-millionth of a meter. It is an extremely small measurement fitting for a solitary wool fiber.
Your average 80’s count wool is about 19.5 μm in diameter. For comparison, the average human hair is about 100 microns wide. Dormeuil, one of the most well-respected cloth houses in England, has a cloth book called “15.7,” and it’s filled with cloths that measure out at this very fine measurement (about Super 160).
Pro tip: Super 120’s-140’s are somewhat of a sweet spot wherein you get a very nice hand but retain excellent durability.
Why Are They Called “Super” 100’s?
Decades ago, spinners Joseph Lumb & Sons began offering the prize “The Golden Bale” to the raw wool entered into its competition that they deemed the finest of them all. For years, nothing higher than 80’s count wool could be grown. One year, a 100’s count wool won. The merchants who won were so astounded and elated that they named it “Super 100’s” and the term stuck.
Nowadays, there isn’t really anything “super” about wool counts under 100. On the other hand, there is a point of diminishing returns as we go up the Super scale. Generally, a Super 180’s cloth is about as fine as you should bother buying. Cloths finer than this (there are some Super 250’s out there that command crazy retail prices) feel amazing but are difficult to tailor and break down too easily.
Again, sticking to the Super 120-140 sweet spot will always work for you.
Length, Strength, Color & Crimp: The Other Wool Quality Indicators
To judge wool by its fineness is, well, fine, but there’s more that goes into it than just a Super number. Superfine wool with no crimp and short fibers is not as high quality as you might think. The other ways we decide wool’s quality is by assessing its length, strength, color, and crimp.
- Length: Longer fibers make yarn that’s less likely to break down. As such, longer fibers are used in higher-end suitings and are more expensive.
- Strength: How does an individual fiber hold up to being twisted very tightly? The stronger the fiber, the longer its lifespan, and the higher its price.
- Color: After washing, how many stains or impurities are present? “Cleaner” wool colors command higher prices.
- Crimp: How many bends does an individual fiber have? Those with higher crimp spin into finer yarn, thus creating a more expensive, luxurious product. This is measured in crimps per inch or crimps per centimeter.
How Is Wool Suit Fabric Made?
Let’s use wool, the most popular suit fabric, as our guide. Here are the steps by which a sheep’s fleece becomes a suit fabric:
- Sheep are shorn with electric clipping machines, with great care to ensure the fleece falls off in one piece. This happens once or twice a year.
- The fleece is washed. This causes it to lose about 50% of its original weight.
- Fibers are blended & combed, separating short fibers from longer, more desirable ones
- Fibers are dyed and spun. This turns them into yarn.
- Yarn is twisted or “folded,” the latter of which takes two strands of yarn and twists them together so that they’re stronger. This is called a “two-ply” yarn.
- Yarn is woven into cloth.
- Cloth goes through a finishing process: it is washed, flattened, shrunk, and mended as necessary.
- Finished cloth is sold to fabric houses.
On Cloth Weight
You’ll often hear terms like “nine-ounce wool” or the like. Very simply, this refers to ounces per yard, so one yard of nine-ounce wool (which happens to be the best all-season weight, in our opinion) has a weight of, well, nine ounces.
Technically, the measurement is ounces per running yard, “running” being the industry term for uncut cloth’s width inside the selvedge, which are the woven edges on a bolt of cloth that prevent fraying.
The Importance Of Weight In Suit Cloth & Wool Weight Guide
There has been a mania for many years regarding cloth weight. Specifically, people go nuts over the finest, lightest weight cloths available, (sometimes erroneously) thinking that light and fine automatically offer better quality.
While lightweight, fine wools are nice, they are not necessarily better, at least not in every instance. Superfine cloths wrinkle more easily and are more difficult to tailor, and a lightweight cloth won’t necessarily keep you cooler as that’s based on a myriad of factors, including lining and type of canvas used in construction.
So, here’s a brief guide to wool cloth weights and the seasons they generally pertain to. Again, this is a guide, not a set of rules.
- 6.5-8.5 oz (210-265 grams): These weights are considered lightweight and are great for men who live in warmer climates. Floridians, southern Californians, and southern Italians should own suits in these weights. If you’re getting married in the summertime, opt for a suit of this weight.
- 9-12 oz (280-360 grams): These mid-weight cloths are generally considered “all-season” or “four season” wools. Our preference is in the 9-10 ounce range in particular, but this is largely dependent on your geographical area and your own body chemistry (that is, if you tend to run hot or not).
- 12.5-14 oz (360-420 grams): We’ve now reached upper-mid or low-heavyweight cloth. These are really geared towards autumn and winter suitings and would be a great option for a man who’s involved in a winter wedding, for example, as it minimizes the need for an overcoat while outdoors.
- 14-19 oz (420-570 grams): This is true heavyweight territory. The George Foremans of wool cloth, these weights are typically reserved for overcoats and heavy tweed jackets. You may find some woolens in this weight range in addition to worsteds.
There’s obviously a lot to know about wool as it relates to men’s suits. With that said, it’s also important to know about other fabrics.
To learn more about cotton, linen, mohair, and maybe even a few fabrics you’ve never heard of, take a gander at our fabrics guide. For more general information on suits, check out our suits home page.