Everyone has an opinion on what is the best thread-count and perhaps everyone has their own idea in their heads of what is meant by thread-count. Hopefully this definitive guide will dispel some myths and give you a better insight when purchasing bed linen.
The thread-count of any fabric is simply defined by the number of threads there are in a square inch of that particular cloth. So for example if you have a 200 Thread-count piece of cloth you should be able to cut a square out 1”x 1” and count 200 Threads running both Top to Bottom (Warp) and Left to Right (Weft)
When talking about bed linen, thread-counts start at around 120 per sq inch and go up over 1,000 per sq inch. The construction of a 120 Thread-count piece of cloth would be 60 threads running in the warp and 60 threads running in the weft. 60+60=120. A standard 200 Thread-count is usually constructed using 118. Threads running in the warp and 91 in the weft. (Actually a 199 Thread-count but they are always rounded up to the nearest 10).
The second important factor when considering thread-counts is the size (denier) of the yarns used to weave the cloth. This is the case whether the cloth is made of Cotton, Wool, Polyester, Nylon etc.
Denier is a measure of the thickness of the yarn/thread. The higher the number, the thinner the yarn is. For example standard 120 Thread-count cotton bed linen would use 30 denier cotton yarn/thread. If you then use the same 30 denier cotton yarn/thread to produce a 200 Thread-count you need to put more threads into a square inch to achieve the thread-count.
Obviously, this gets harder and harder as you increase the thread-count, if you keep using the same thickness of cotton yarn. Eventually it actually becomes impossible.
The maximum thread-count that can be produced using 30 denier yarn is around 250 threads per sq inch. Obviously as the thread-count is increased the fabric becomes denser and denser as more threads are squeezed into the same area.
When producing bed linen, as you increase the thread-count the size/denier of the yarn used decreases at the same time. For example most 200 Thread-count bed linen will use a 40 Denier Yarn. (Remember the higher the number the thinner the yarn). 300 Thread-count is often made using 60 Denier yarn, 400 Thread-count uses 80 Denier Yarn and so on. The highest denier in general use is around 140 and this would be used in very fine cotton or silk fabric used to make expensive shirts.
The above rules apply when good quality cotton yarn is used. Unfortunately quite a large amount of bed linen is produced using lower quality yarn. Lower quality thin yarn has the tendency to break during weaving and so to avoid this happening it is possible to spin to yarns together (a bit like plaiting), this then produces a thicker stronger yarn. This is the woven into various thread-counts.
The trouble with using 2-ply yarns as they are called is sometimes the thread-count is misrepresented. For example if you have a 200 Thread-count which uses 2-ply yarns (2 low quality yarns spun together), this is still a 200 Thread-count not a 400 Thread-count which it is quite often sold as. This is how super-high thread-counts are often achieved. Let’s take 1,000 Thread-count for example. This should use very fine 100 or 120 Denier yarn and be woven 560 threads on the warp and 438 on the weft but what can be done and often is, is an 80 denier 2-ply yarn is used and woven 233 on the warp and 264 on the weft.
This is actually a 500 thread-count but because it uses low quality 2-ply yarns it is often sold as 1,000 thread-count counting each 2-ply yarn as 2 separate yarns. Not illegal, but immoral.
The other problem with using 2-ply yarns is because they are thicker when they are used to produce high thread-counts they are crammed into the square inch area and this just makes the fabric too dense. Bed Linen can end up feeling like curtain material or canvas. Cramming yarns in also affects how breathable the
fabric is and this is important with bed linen. Not breathable means too hot.
The weaving process is just the first part of producing bed linen and already there are potential minefields. The next step is finishing the cloth. The finishing process is as important because this is where the whiteness is achieved, shrinkage is reduced and the overall “hand-feel” of the fabric is produced.