Every fabric we use has to pass one test before it gets near a pattern: 50 home wash-and-dry cycles. Not a machine in a factory. A regular washer, regular detergent, and the same habits you have at home. Here is how it works and why we bother.
The setup
We cut three swatches from every fabric candidate, each 20 by 20 inches. One stays in a drawer, unwashed, as the reference. The other two go into the wash.
The first test swatch follows our care advice: cold wash, inside out, no softener, hang to dry. The second gets a harder life. Warm wash, a tumble dry on medium every fifth cycle, and the occasional night left damp in a gym bag. We want to know how a fabric behaves when it is looked after, and also how it behaves when it is not.
Each swatch is marked with a 10 inch box in thread before the first wash. That box is what we measure.
What we measure
After cycles 1, 10, 25 and 50, we lay each swatch flat and measure the thread box in both directions. Our limit is 3 percent. If the box shrinks or grows more than that in either direction, the fabric is out. Most fabrics that fail do it early, in the first ten washes.
We also check four other things at each stage:
- Color. We put the washed swatch next to the unwashed one under the same window light. Black is the hardest. If it starts to look charcoal, it fails.
- Recovery. We stretch a strip by half its length for ten seconds and measure how far it comes back after one minute. CoreFlex has to return to within 2 percent.
- Surface. We look for pilling, fuzzing and any change in the hand feel.
- Seams. A short sample seam is sewn into each swatch. We check that it has not puckered, twisted or opened.
What fails, and why it matters
In the last round we tested eleven fabrics. Four made it through. The most common failure was color loss on darker shades, followed by elastane that lost recovery after repeated heat. Two fabrics that felt beautiful on day one were pilling badly by wash 25.
That is the point of the test. A fabric that feels great in your hand at the store tells you very little. What matters is how it feels on a Thursday in October, after six months of sessions.
The three fabrics we use today, AirKnit, CoreFlex and TerraFleece, all passed. You can see their full specs on our Fabric & Fit page, and the habits that keep them that way in the care guide.