The following is a reply we received from Sirdar about knots a customer had found in a Sirdar yarn. We thought it was interesting and have replicated it completely here.
As far as we are aware there are no industry standards for the amount of knots allowed per ball although a figure of 2 per ball is often quoted by knitters.
A number of different factors affect how many knots are in a dye lot.
If a particular shade is popular and can be produced along a colour spun route there will be less knots. This is because the actual fibres are dyed in their raw state and then spun.
This is where small dye lots are produced by dyeing hanks of ecru yarn. The hanks are relatively small and during the winding process they can tend to become tangled and break thus requiring knots to join them together. At least 3 hanks will be wound onto a cone so, excluding breaks, there will be a minimum of 3 knots per cone. These cones are then balled and the cones need to be tied to each other during this process to minimize machine stoppages. Hence there will be at least one knot per kilo of yarn produced.
Some of these yarns can be produced from a number of different components to produce different effects and textures. The more yarns that are twisted together, the more knots will be produced in the overall yarn.
Ultra Chunky Yarns:
These yarns are so bulky that only a small length can be wound onto a cone. Obviously the more cones there are, the more knots will be added during processing.
Unfortunately, the most expensive yarns seem to have more knots than the cheaper ones. This is because the more expensive fibres such as mohair, angora, silk etc, tend to be produced down the hank dyed route.
We hope this information helps you to understand the occurrence of knots in hand-knitting yarn