Must say I find that pure wool washes very well - as long as you don't do what I did with my new washing machine - no 'just spin' setting, so you have to fiddle and faff with the 'rinse and spin' setting. And I mis-faffed, and a nice new, LONG pure wool jumper, which I'd actually bloody well knitted in expensive yarn, ended up a badly shrunken thing fit only for the bin.
On its first wash, too! There was some very unladylike language, I can tell you.