How to read a fabric composition label properly
The composition label on a garment is the most honest thing about it. It's a legal requirement, it can't be dressed up in marketing language, and it tells you. If you know how to read it. A fair amount about how the piece will wear, wash, and age. Most people glance at it and move on. It's worth slowing down.
What the percentages mean
The percentages on a composition label refer to the weight of each fibre relative to the total fabric weight. A label reading '80% wool, 20% polyester' means that by weight, 80% of the yarn is wool and 20% is polyester. This matters because the properties of the fabric. Warmth, breathability, drape, how it pills. Are determined by whichever fibre dominates.
A small percentage of a secondary fibre is often there for a good reason. Five percent elastane in a trouser gives it recovery without compromising the hand of the fabric. Ten percent nylon in a sock makes it last longer. The question to ask is whether the secondary fibre is there to improve the garment or to reduce the cost of making it.
When a blend is a red flag
A linen shirt that's 55% linen and 45% polyester is not really a linen shirt. It will feel different, wash differently, and age differently from a shirt that's 100% linen or even 80% linen. The polyester is there because it's cheaper than linen and it reduces the wrinkling that some customers find off-putting. Whether that's a trade-off you want to make is up to you, but you should know you're making it.
The same logic applies to wool. A coat labelled 'wool blend' could be 60% wool or 20% wool. Both are technically blends. The label will tell you the exact figure if you look for it, and that figure is worth finding before you spend £300 on a coat you expect to last a decade.
- Linen/polyester blends above 30% polyester: the linen properties are largely lost
- Wool blends below 50% wool: warmth and drape are significantly reduced
- 'Viscose-rich' fabrics: can drape beautifully but are often fragile when wet
- Acrylic in knitwear: pills faster than wool and doesn't breathe
What the label doesn't tell you
Composition labels don't tell you about yarn quality within a fibre category. Merino wool ranges from 15 microns (very fine, very soft) to 24 microns (coarser, more durable). Both are 100% wool on the label. The difference in how they feel against skin is significant.
Labels also don't tell you about construction. Seam allowances, how the hem is finished, whether the lining is sewn or fused. A 100% wool coat with a fused lining will delaminate faster than a 90% wool coat with a properly sewn lining. The composition is only part of the picture.
If you're ever unsure about a piece in the shop, ask. We know the composition of everything on the rail and, in most cases, we know the mill it came from.