A pre-fulled yarn (also called pre-fulled or pre-washed) is a yarn that has already undergone a fulling pre-wash before being sold to the end customer, whether a private individual or a knitwear company.
Here's what it means in practice:
Fulling is a finishing process typical of cashmere and fine wools. It consists of a controlled treatment with:
hot water,
soap or mild detergents,
light mechanical movement.
It helps the fiber open, making it softer, fuller, and more voluminous.
When a yarn is already fulled, it means this process was done before being sold, not after the garment was made.
✔️ The fiber already appears more open and soft.
✔️ The yarn has a slightly "hairier" or softer appearance.
✔️ The rock is more compact and lighter to the touch than a raw yarn.
✔️ The knitted/crochet/machine-knitted piece will experience less shock during the first wash: it will behave more predictably.
Higher dimensional stability: less risk of sudden shrinkage.
More uniform final feel right from the start.
Ideal for those who want to immediately see how the finished garment will "bloom."
Perfect for recycled yarns or yarns with short fibers, as it improves cohesion.
Compared to a raw yarn, a fully-felted yarn tends to yield a little less during processing.
It's always a good idea to make a sample and do a small test wash, because each yarn has its own degree of fulling.