Have you ever looked at stitches you've just cast on to find that you
don't have neat, distinct strands and it's even difficult to count them
without physically separating the fibers?
Is it a problem with the yarn? No. As you can see in the next
picture, a further 10 stitches have been cast on, but this time they are
all clearly distinguishable. So what's going on?
The answer lies in the twist.
Twisting fiber imparts strength to a yarn. It makes the fibers harder to
pull apart lengthways and the yarn therefore harder to break. You can twist
in either direction. If you hold a length of fiber one end and twist the
far end to the left you get an S twist in your yarn. If you twist to the
right instead you get a Z twist.
Most manufactured single plies are spun with a Z twist. To ply these
Z-spun singles together they are spun with an S twist to give a balanced
plied yarn. Almost all yarns available to us as knitters and crocheters are
made in this way, i.e. Z twist if they're single ply and having a final S
twist if they're plied.
Knitting or crocheting with a yarn changes the amount of twist. How it
changes depends on the final twist direction of the yarn and the direction
in which you wrap the yarn around the needle.
Does that matter? Adding more twist to your yarn causes it to tighten up,
making it slightly stronger and less susceptible to pilling, and also
making the stitches easier to work and less likely to split. Reducing the
twist in a yarn makes the fibers and plies separate and it is more
difficult to work without splitting the yarn.
This table shows how different techniques affect S-plied and Z-plied
|Knitting 'Western' method
|Knitting 'Eastern' method
|Knitting 'Combined' method
Knit ― Adds twist
Purl ― Removes twist
Knit ― Removes twist
Purl ― Adds twist
A note on different knitting methods: Most knitters in America / UK /
Western Europe / Australia are 'Western' knitters - the right hand leg of
the stitch sits at the front of the work, i.e. closest to you on the needle.
Whether you hold the yarn in your right hand (English or throwing style) or
your left hand (Continental or picking style) you are still using the
'Western' method. 'Eastern' knitters have the right hand leg of their
stitches on the far side of the needle, work into the back of all their
stitches, and take the yarn round the needle in the opposite direction to
form a new stitch. The 'Combined' method uses a mix of the two.
So the good news for most 'Western' knitters is that they introduce more
twist into the commonly available S-plied yarns. In this picture, showing a
swatch I made using an S-plied yarn, the stitches on the needle have plenty
of twist where they were made with the Western knitting method, but the
plies have separated where the Eastern method was used.
For crochet, the opposite is true - in the pictures below, the plies of
the S-plied yarn have separated, while the stitches of the single with its
Z twist are tightly spun.
Twist is added to this Z-spun single when crocheting
The plies of an S-plied yarn untwist when crocheted
What does that mean for your knitting and crochet? The twist in your yarn
can make the difference between sailing along row after row, hardly looking
at your work, or finding that you split your stitches if you don't pay
close attention. Of course that doesn't mean that a knitter has to learn
the Eastern knitting method in order to enjoy a single ply yarn, and
crocheters are very used to working with S-plied yarns. After a few rows
your fingers become used to your yarn and the level of care that you need
to take to form stitches with it. Plus any stray loops in your knitting can
often be fixed by dropping a stitch down to that point and collecting them
But it is easier to work with yarn when you are adding twist as you work.
Many crochet cotton threads are Z-plied for this reason and there are a few
Z-plied yarns available for crochet and also for twined knitting, a
technique which leads to excess twist in an S-plied yarn.
Yarns with a 'cabled' or 'crepe' construction also usually have a final
Z-twist. In these yarns, singles are Z-twisted, then plied together with an
S-twist, then those 2 ply yarns are plied together again with a final Z
twist. Cable yarns are said to be very hard-wearing and less susceptible to
pilling, though all that plying means they won't feel as soft as a yarn
with a lower total twist.
Finding Z-plied yarns
You can search on YarnSub for any of these Z-plied yarns.
Even if you can't get hold of a Z-plied yarn, at least avoid using a
loosely S-plied yarn for crochet, since you'll be taking even more twist
out as you work with it.
And if you don't like the lack of twist (as in the picture at the top)
that results from using a Z-spun single ply yarn for a cable cast on, try
working it the 'wrong' way: wrap the yarn for the new stitch over, down and
round the needle (rather than under, up and round), and slip the new stitch
off the right hand needle by moving the left hand needle through the new
loop towards you, not away from you. Both of these actions add twist to a
Z-spun yarn instead of removing it and make little difference to the look
of the cast on edge.