Why You Need Merino This Winter

Merino sheep are mostly farmed in Australia, South Africa and New Zealand. And if you think about the diversity in temperatures across these places you can get an idea of the conditions merino wool works in. Take Central Otago, for example. Even through freezing winters and hot, dry summers, stock are equally at home in temperatures above 30°C as they are well below freezing.

Once it’s shorn and processed, Merino wool is made available to us in a few different sizes. Measured in microns, this number refers to the diameter of the fibre itself. The lower the number, the finer the yarn. But just remember that finer yarns are softer, so they require more care compared to synthetic fabrics.

At Macpac, we select yarns between 17.5 and 21 microns depending on the end use of a garment. When it comes to naming, the numbers (like a 180 pullover or a 320 jacket) refer to the fabric’s weight — measured in grams per square metre. Just like microns, a larger number = a heavier fabric.

In comparison, traditional wool looks thicker and coarser than merino under a microscope. It feels that way on skin, too.

Where it doesn’t work so well

Synthetic options are great if you’re really pushing your limits, so we wouldn’t recommend merino if you were, say, heading out for an hour’s run in the sun. That’s because where hydrophobic synthetic layers work by moving moisture directly from your skin to the outside of the garment where it can evaporate, merino absorbs moisture before moving it outside.

You might have experienced this yourself, where your shirt looks like it's soaked but you’re not feeling much of a chill. The lightness of merino wool usually comes into effect not long after — evaporating the sweat and drying in next to no time. This lightness, however, can result in less strength compared to synthetics of a similar weight.