Numbers Game

Why the numerical designations—Super 100s, Super 120s, Super 180s—for ultra-lightweight wools don't mean what you think they do.

By Gary Walther

The thread of this story is the numbering system used to describe the new breed of super-lightweight, high-twist wools. Pioneered by Italian mills about ten years ago, these fabrics are made using high-tech machines that spin wool lighter and finer than it's ever been spun before. The various grades of cloth are referred to as Super 100s, Super 120s, Super 150s and so on, up to Super 200s, which Oxxford Clothes started using last year for a line of suits. (As far as I know, this is the top of the super-lightweight wool pyramid right now.)

The problem is the impression left by the numbering system. Set up as a shorthand for describing the fineness of wool fibers, it has, in the process of trickling out into the marketplace, come to be taken as a quality ranking. It's easy to assume a Super 120s wool must be better than a Super 100s wool and not as good as a Super 150s wool—in short, the higher the S-number, the better the fabric.

That's simply not true, and no less an authority than Paolo Zegna, the textiles division president of Ermenegildo Zegna, describes the S-system, as it's known in the trade, as "a very big confusion." Zegna doesn't use S-numbers at all, preferring to describe its lightweight wools as High Performance or 15 Milmil 15, for example. Still, the S-numbers persist, a lingua franca that's irresistible because it reduces a complex subject to a sort of yardstick.

The S-system dates back to the 18th century (also known at the time as the worsted count system), and then as now it denoted the fineness of a given bale of wool. In those days finished yarn was coiled into 560-yard-long loops called hanks. The S-number indicated how many hanks could be gotten out of a pound of wool. The finer the wool yarn, the farther it would go. The S-scale ran from 30s to 100s, then the finest wool available. (Today 100s wool is practically the bottom rung of the S-scale.)

The S-scale remains even though hanks are long gone. Now the number refers to the fineness of the wool as measured in microns (one-millionth of a meter). Does that mean finer is better? Not necessarily. As Paolo Zegna explains, "You can have a good 15-micron wool or a bad 15-micron wool." (Finer does mean more expensive: Oxxford's suits made from Super 200s wool retail for $14,000.)

Fineness is just one quality component: Length, strength, color, and crimp are also important, with the first two particularly so. Length is critical because the longer the fiber, the stronger the yarn that can be spun from it. Strength is critical because the yarn must be twisted very tightly (hence the name high-twist fabric) to achieve a fine weave. The way in which the fabric is finished also plays an enormous role in the feel and look. At Dormeuil, I have seen Super 100s wool that felt as sumptuous as Super 120s or 140s because of the finishing.

But there's a mania among consumers and manufacturers for fineness and lightness. "There's been a revolution in the making of a garment," says Zegna. "The heaviest fabric used today is lighter than the lightest fabric used ten years ago. Ten years ago '13-micron wool' would have meant nothing." Pier Luigi Guerci, president of Loro Piana, adds,"Fifteen years ago there was no production under 17 microns. Now, thousands of bales are produced."

To get such fine wool, sheep flocks have to be specially bred and managed so they grow the requisite fleece. ("Hothouse sheep," quips Ashley Dormeuil, director of Dormeuil.) The quest has even spawned a face-off between New Zealand and Australia, the world's largest producers of fine wool, to see which can produce the finest bale of yarn. In 1998 Australia took the crown with a 13.3­micron bale; last year New Zealand bested that by 0.2 microns. How thin is that? Well, one human hair is 40-120 microns thick.

The irony of this micron mania is that the finest wools (Super 150s and above) don't necessarily make the best garments. For one thing, these fabrics are hard to tailor because the material shifts so easily when it is sewn. (Italian tailors say that the wool is "nervous.") Such wools also wrinkle almost as easily as linen. They are delicate—Paolo Zegna says a Super 180s is like a Ferrari—and not as durable as a less-fine wool. And suits made from them have to be dry-cleaned sparingly. "It's a high-maintenance garment," says Gianni Campagna, the Milan custom tailor who made the suits, all Super 150s, that Pierce Brosnan wore in The Thomas Crown Affair. "If you stain it, you can only spot-clean it. Or buy a new suit," he adds jokingly.

So what should you do? Make Super 100s and Super 120s the mainstay of your wardrobe. They are durable, resilient, and today's fabrics are superb. Treat the Super 150s and Super 180s as caviar (wonderful, but not to be eaten every day). For these really are connoisseurs' suits. "The pleasure of the weave is something special," concedes Paolo Zegna. Says Pier Luigi Guerci, "The difference to the touch between 17.5 microns and 13.4 microns is enormous. The latter is smoother, creamier. Yet both are fine fabrics." And that's the thing: Ultimately it is the look and tailoring of the fabric that matter most. Everything else is just a number.

A Fine Madness
Each year Loro Piana bids for the finest bale of wool produced by Australia or New Zealand, and in the past the company has been able to secure these lots. It keeps the bale in its Quarona, Italy, headquarters until a finer bale is produced. The dethroned bale is spun into yarn and turned into Record Bale fabrics for custom-made suits that retail for about $11,500. For information, call 212-980-7961.