Today I had my hands on a skein of yarn dyed by a customer who should have known better. Two things … the skein smelled of vinegar … and … it had been scoured. One screams that they dyer didn’t do enough, the other that they did too much!
When dyeing protein fibers such as the yarns from Wool2Dye4, I use white distilled vinegar to set my depot, and have never had a skein smell like it. It’s simple: Yarn will smell bad if you use too much vinegar. That is the simple truth. Use a lighter hand when you add distilled vinegar to your depot and then wash every skein with a gentle wool wash, like Eucalan. That is all that is needed, and if your yarn has the smell of vinegar, then it is screaming that you did not take the time to do it right. Do you consider yourself a professional? Take a sniff at your packaged skeins to be sure.
Why do we say not to scour our yarns or use a stripper such as Synthrapol? Two reasons: Scouring agents are meant for cellulose fibers, not protein fibers. The second reason is that our yarns are steamed as an extra step at the mill. That extra step strips away any lingering lanolin or machine oil which dyers who scour say they are taking care of. No! The skein I had today had been given a soak in something like Synthrapol, and it feels like straw. Nothing I did could bring it back to life, and what a shame. I say this because I know that dyers are selling yarns where they have scoured our yarns and there is absolutely no reason for it.
With our yarns, there is absolutely no reason to overdo either of these two harsh chemicals. Maybe with other mills, but not with the yarns you buy from Wool2Dye4 because our mill performs that extra step of steaming. There reason to use distilled is because it serves as the acid required to set acid dyes designed for protein (e.g., wool) fibers. There is absolutely no reason to use a stripper or scouring agent such as Synthrapol. In fact, they are counter-indicated for protein fibers, because they slowly eat away at the wool fibers and erode them.
Scouring agents are used in dyeing cellulose fibers, such as cotton. Not wool
After dyeing, give your skeins a nice bath with a stay-in wool wash, and hang to dry.