Adding twist brings wool fibres together and helps yarn integrity, but it also reduces spaces available to trap air. Woolmark's Merino Air method addresses that trade-off by blowing fibres into a fine knitted tube. The outer network provides support while the filling remains relatively loose and bulky.

Low-Twist Yarn Structure Preserves Space for Insulating Air

The result targets warmth for a lower garment weight, particularly in coarse-gauge knitwear. It illustrates why yarn thickness and yarn mass are different properties. A lofty-looking strand can contain substantial air space, with its construction determining how that structure survives knitting and wear.