In its natural knitted state, wool will shrink when washed in a machine and/or is tumble dried. As it needed to be carefully hand-washed, woollen garments fell out of fashion and were replaced with polyesters and other synthetic fibres. Now we’re moving into a new era where we know synthetic fibres are bad for the environment and also not so great to wear against our skin. In the same time period, we’ve developed an easy care treatment for wool – enabling it to be machine washed AND tumble dried. A whole new generation of wool wearers is emerging and Interknit is at the cusp of the change.

Why does wool shrink?

To explain how we ended up with wool that won’t shrink, we first have to look into WHY wool shrinks, or to use an industry specific term, felts.

Wool fibres are natural fibres, a bit like human hair, and like human hair, they have microscopic scales along their length. These scales are what helps the wool cling together when it is spun and they provide the natural elasticity of wool. Unfortunately, exposure to heat, agitation, soap and water causes the scales to swell and crimp and stick together much better than we need them to. If they crumple enough, they will shrink the garment entirely in a process we call felting.

How does an ‘Easy Care’ treatment prevent felting?

The easy care treatment reduces the scales on the fibres so that there is less to swell and crimp and therefore the process eliminates felting when the garment is exposed to heat, agitation, soap and water.

There are two ways to reduce the scales, one is to coat the fibres in a polymer which essentially stops the scales from being able to join together and crimp. The second is to wash the fibres in an acid bath to remove the scales from the fibre.

What are the advantages of ‘Easy Care’ treatment?

Clearly the best advantage is that you are now able to machine wash and tumble dry your garment which saves time and effort and gives you a failsafe against laundry accidents. (Read our Garment Care page if you’re prone to woollen laundry accidents).

Another benefit of the easy care treatment on Merino Wool is that it continues to hold dye effectively, unlike other fibres which tend to lose colourfastness when treated with easy care.

Wool is naturally a very elastic fibre and some of this elasticity is due to the scales on the fibres. While some easy care treated fibres will stretch out horribly with washing, Merino wool retains its elasticity and washes and wears like usual.

What are the disadvantages of ‘Easy Care’ treatment?

The main disadvantage of Easy Care treatment as it exists today (2018) is the impact it has on the environment. Already wool production has a large water footprint and while some of this water is considered grey water (can be reused), when the fibres are washed in an acid bath, this becomes pure waste water.


The silver lining here is the development of organic easy care techniques which will lessen the environmental impact of easy care treatments. As soon as these become commercially viable, the easy care treatment of Merino Wool will be obvious choice for everyday garments adding yet another great feature to an already feature packed fibre!