If I were to wash one of my wool sweaters in hot water, it would shrink pretty dramatically. What would happen if I washed a sheep in hot water? (I hasten to add I don’t have a sheep and have no intention of hijacking one and taking it through the car wash.) Does wool shrink in hot water because of inherent properties, or is there something in the process of turning wool into cloth that gives it this tendency?
I live in the American west, where, as they say, men are men and sheep are nervous. When I finally summoned the courage to ask a couple of old duffers who raise sheep, they laughed but never answered the question. So I turn to you, Teeming Millions…
Given the temperature in washing machines for hot water, and the length of the washing cycle, the sheep could easily be scalded or burned over most of its body. Very painful, and quite possible that the sheep would die from this.
Time to add personal experience to the thread, for I have washed a sheep in hot water.
It was a cool day, and the water was more “really warm” than scalding hot. My daughter was getting her lamb ready for a show, and I helped her to wash it. The wool–and the sheep–showed no sign of shrinking. Woolite, incidentally, works well for whitening the wool while it’s still on the sheep.
This is not correct.
There are two inter-related processes going on.
Wool will felt due to interlocking of the fibre scales when fibres are rubbed past each other. This can occur in hot water, cold water or without water.
Yarn will felt more because the fibres in a yarn are both freeer to move and more linearly aligned due to the carding process. On the sheep one end of the fibre is fixed in the skin, there are also cross fibres within the wool staple (angled, not interwoven).
Wool on the sheep will felt if the animal rubs themselves for a period against a tree or post because they have external parasites. In a fleece this is termed “cotting” but it is the same felting process.
When the fibres are under stress the alpha helixes in the microfibrells within the fibre stretch. It’s the interchange between alpha helixes and beta pleated sheet arrangement.
When dry or in cold water when the tension is released the helixes return largely to their original state.
In hot water or steam when under tension the fibres retain their stretch. In effect the “S-S” cysteine bonds re-align themselves in a process called stress release.
Shrinking of wool garments occurs because the fibres are stretched in the knitting/weaving process. When washed in hot/warm water the stress release process occurs and the fibres contract to closer to their original .
Wool on the sheep will not shrink were the animal to be placed in a warm bath because the fibres in the fleece are not under tension. But, as stated above, any aggitation e.g. washing will move fibres past each other and cause felting to some degree and more so in warm water than cold.
From experience, cat fur gets quite matted in a washing machine. No shrinkage, though, and they often live to tell the tale. (Tumble driers have a lower survival rate, IME.)
I can’t comment on sheep, they are much less likely to take naps in washing machines.
Awww! I love sheep when they’re all fluffy and white. One of my favorite parts of the fair to visit [my maternal grandfather was a sheep judge, so I got to hang out with him while he judged.]. I’d love to have a couple but alas, daHubby has put the kibosh on that.
