After the first attacks of cold weather, it is logical to look for a system of defence that starts with a warm pair of socks. The question of the choice of materials arises and many clients ask us to enlighten them on the choice of merino wool or cashmere. What are the differences between merino wool and cashmere ? What are the advantages and disadvantages of each? Should we prefer woollen socks or cashmere socks ?
If softness was measurable, it would depend on the fineness of the fibres. The finer the fibres, the softer the yarn. A softer yarn will make for a softer sock. At this little game, cashmere wins the round for softness because cashmere fibres are on average finer than merino wool fibres. Merino sheep generally have fibres with diameters between 19 and 23 microns, whereas cashmere goats have fibres of 14 to 18 microns in diameter. Note that these are averages. In fact, the finest wool in the world has been obtained from … merinos. In 2010, Zegna beat its own record of 2003 with a wool of 10 microns. Zegna succeeded in weaving a piece of fabric 60 metres with fibres of an average of 11.1 microns!
The fabric had to sell at a price higher than that of vicuna.
It is the turn of merino wool to win its first round. Merino wool is rather more durable than cashmere. This is explained by the length and diameter of the fibres. The shortest fibres have a slightly greater tendency to pill. The length of cashmere fibres is between 30 and 90 mm and for merino wool it is between 30 and 120 mm. Pilling will cause garments to wear a little faster. Merino wool is therefore more durable than cashmere. The most durable wools are the old tweeds made of coarse wool, with thicker (so less soft) and more resistant fibres.
Cashmere regains the advantage. The fineness of the fibres allows cashmere to trap more air than wool with an equivalent gauge of yarn. To put it otherwise, imagine two cylinders, one filled with fine fibres and the other with thicker fibres. Mechanically, the cylinder filled with fine fibres will trap more small air bubbles. Air is an excellent insulator (on condition that it can be trapped). It is for this reason that cashmere is a little warmer than merino wool, all other things being equal.
It is also for this reason that cashmere is warm when it is cold, while being lightweight when it is warmer.
The advantage goes to merino wool, which, except in cases of extreme fineness, is less expensive than cashmere. This is explained by the abundance of merino wool production compared to that of cashmere.
A draw! There is no winner strictly speaking! You must ask yourself on what criteria will you base your choice. Do you look at the price of socks? Are you sensitive to softness? And warmth? Do your socks wear quickly? Now you are ready for a well-informed choice!