Remember my A Conventional yarn blog, where I explained about spinning basics and balanced yarns? How we knit has an effect on the yarn. Conventional hand-knitting is created by spiraling the yarn around the needle in an anti-clockwise direction (viewed from the needle tip).
When you spiral something, you add twist.
For plied yarns, spun Z and plied S, this tends to add S twist, tightening up the ply. With some plied yarns this can result in the yarn leading to the ball becoming twisted and wanting to ‘ply’ itself back in the Z direction. (You would probably feel the need to untwizzle the yarn periodically to dissipate the twist.)
If you rotate the yarn in the unconventional direction (clockwise viewed from the needle tip) you might notice the plies of the yarn starting to separate on the needle. You are slightly unwinding the ply. Try this by rotating a yarn around a needle (you don’t need to actually knit it).
The Madelinetosh Merino Light that I am using is a single spun Z, and not plied. On the near layer of my double knitting I am slightly untwisting it (adding S twist, will reduce the Z) and my stitches are quite relaxed and fairly balanced. This means the stitches will sit fairly normally, like a V.
But on the far side, where all my stitches are purled with alternative rotation (clockwise viewed from the needle tip) for more evenly sized stitches, I’m adding Z twist. So, I’m adding Z twist to an already Z twisted yarn. The result is that these stitches are far less balanced, and the stitches sit slightly lopsidedly. More like this, \|, rather than \/. Look closely at the picture. The right-hand legs of the stitches run more vertically.
With a conventional plied yarn the difference in twist is the same, but the appearance is not so clearly different; my theory is that the complexity of the plied yarn structure disguises the variance better!
I don’t dislike the appearance of the stitches on the far side of my Mardi Gras blanket, but I just don’t wish to mix them with more normal looking stitches, and for this reason I am sticking to using only Madelinetosh singles yarn in this project!
For more about stitch balance and structure and some really scary rescue techniques, try my class Fearless Knitting – Empowering Techniques for Every Knitter on Craftsy!