Not Your Grandma’s Wool


Fabric is at the core of every Mack Weldon product.  We pride ourselves on developing our own custom blends and never buying anything “off the shelf.”  It takes a lot of time to get fabric development right, so when we do introduce a new fabric, there’s always a good reason why.  This is the story of Merino Wool.

Last winter, we launched a collection of long underwear and long sleeve shirts made of merino wool and Tencel.  That custom fabric blend created a garment that was soft, lightweight, antimicrobial, moisture-wicking, thermoregulating, and wrinkle-resistant.  Customers loved it, so we’re bringing both products back this week just in time for winter.  So, what’s the story behind merino wool?  With that many performance attributes, it almost sounds too good to be true.  Trust us.  It’s the real deal, and it’s all thanks to a sheep that hails from New Zealand.


There are many different mammals capable of producing the hair that gets spun into wool.  Alpacas, antelope, goats (cashmere), llamas, rabbits, and sheep are all sheared to produce various types of wool.  In the U.S., the most common forms of wool come from sheep.  While all sheep aren’t created equal, wool does share several characteristics regardless of the animal that grew it that make it a very attractive fabric:

  • Water-Resistant – There’s nothing worse than wet clothes, especially in colder weather. Wool fibers have what’s called lanolin on them (it’s a wax secreted by the glands of the sheep) that can repel outside moisture from rain and snow.  The fibers are also arranged in small overlapping sections like shingles on a roof which aid in repelling moisture.
  • Insulating – Unlike other fibers which are straight and smooth, wool fibers have a natural crimp (waviness) which helps produce tiny insulating air spaces that trap dead air. Trapped air is very good at preventing heat from passing through it.  The effect is similar to insulation inside the walls of a house.  That same fiber crimp also makes the garment elastic and resilient.
  • Moisture-Wicking – Wool doesn’t just keep you warm though, it can also cool you down. Sound contradictory?  Hear us out.  The inside of a wool fiber is hollow which allows it to absorb up to 30% of its weight in moisture without becoming damp and clammy.  As temperatures rise, your body sweats in an effort to cool you down.  Merino wool aids in that effort by quickly absorbing the sweat from your skin into the wool fiber and then releasing it to outside world, keeping you dry and comfortable.
  • Antimicrobial – Wool doesn’t retain odor like polyester or polypropylene. The same lanolin and fiber arrangement that keeps out water, also does a great job repelling bacteria, meaning fresh smelling clothes for days.

Throw in anti-wrinkle and anti-static properties, and you’ve got one workhorse of a fabric.  So why, then, is wool most commonly associated with itchy, uncomfortable Christmas sweaters from grandma?  Because, grandma wasn’t using merino wool.


Merino wool comes from Merino sheep which are largely found in the Southern Alps of New Zealand (in fact, sheep outnumber people in New Zealand by seven-fold).  Temperatures in the Southern Alps can reach 95° F during the summer and -4° F during the winter which explains why the sheep developed a thermo-regulating coat like wool.  The difference between merino wool and grandma’s wool is that fibers from merino sheep are the finest on Earth, making them incredibly soft and lightweight.  It’s all about the diameter of the follicle (measured in microns, because it’s that small).  The smaller the number, the softer and lighter the fabric.  Merino wool can be anywhere from 23 microns on the wide end to less than 15.5 microns on the ultrafine end.  Human hair is 40 microns and your garden variety sheep’s wool can reach into the mid- to upper-30s.  It’s commonly believed that cashmere is the softest wool on Earth, but those who really know their fabrics, know that ultrafine merino beats cashmere any day of the week.


Merino wool is truly a remarkable fabric.  It’s the softest, lightest, and most breathable wool in existence.  It adjusts to the needs of your body temperature and smells fresh for days, making it the ideal base layer for everything from cold urban commuting to hitting the ski slopes to crawling under the covers at night.  It’s truly “For Daily Wear.”  All thanks to a sheep in the Southern Alps of New Zealand.

Check out our entire line of merino products here.  And for all your cold weather needs, stop by our cold weather shop.

Author: Charley

Charley is Director, Finance & Operations at Mack Weldon.