By Jock Merriman · Founder, Sir W. Merino · Fifth generation in Australian Merino since 1880, Merryville Stud, Boorowa NSW
Yes, in most cases. A superfine merino shirt can usually be worn five to seven times between washes, so a week of travel is realistic, especially if you rotate two or three shirts and air each one overnight. The limits are heavy sweat in humid heat and spills, and those you wash.
I can answer this with some confidence because my family has been in Merino wool since 1880 and I grew up around the fibre. I also test it the unglamorous way. This summer I took three merino shirts through fourteen days across Italy and Ireland in a carry-on, and I did not wash any of them.
Why doesn't merino smell after a few wears?
Wool takes moisture in as vapour, inside the fibre, rather than leaving it as damp on your skin. Bacteria are what make a shirt smell, and they have less to work with. It is the fibre's structure doing this, not lanolin, which is scoured off before the wool is spun.
How many wears between washes?
Five to seven is a sensible planning figure. Our care guidance is to wash cold on a wool cycle every five to ten wears and to dry flat. One customer who trains hard told us he stretched a Cassius to seven wears with no smell.
What should I do with it each night?
Hang it somewhere with moving air for a few hours. The fibre releases the moisture it took on, and the shirt is ready again by morning. There is no need to wash it in a hotel sink.
When should I wash it anyway?
This is not unlimited, and I would be doing you a disservice to say otherwise. After heavy sweat in humid heat, after a spill, or any time it smells, wash it. Merino resists odour; it does not repel dirt.
Which shirt should I try this with?
The one I travel in is The Bruce, a short-sleeve button-up that goes from a morning flight to dinner. It is $125, with free US shipping and 30-day free returns.
— Jock
