Wool, what's breed got to do with it?

A few weeks back we announced the launch of a new blog series about fiber.  Well since then, we've prepped, attended and recovered from Creativ Festival, and so its time to get back to the conversation about fiber.

And the place we are going to start with is wool, and learning differences between sheep breeds based on their fleeces. 

Wool is an incredible fiber, it keeps you warm, it keeps you dry and it can even keep you from smelling bad.  Not only that, because of it's structure it has incredible bounce and resilience, that makes it possible for your socks and sweaters to get stretched out but bounce right back to the shape you had knitted it into.

Wool comes from sheep, and while when most people think of sheep they think of a fluffy white sheep from the Serta Commercials, sheep are incredibly diverse and their fleeces have very different qualities. 

This is what you get when you put "sheep" into Google Images.

This is what you get when you put "sheep" into Google Images.

From Icelandic to Merino, there is a world of sheep out there, and by learning how to understand the different breeds you can put their fleeces to work for you.

In order to compare breeds we need to know a few things about their fleeces so that we can compare them fairly.  When looking at a sheep's fleece, there are two main characteristics that we want to consider, the fineness of the fiber, the length of an individual fiber and the crimp of the fiber.

First, lets talk about fineness.  The fineness of a fibre is generally quantified in microns, human hair is around 90 microns.  The sheep fleeces have a good range of fineness, from the outercoats of Icelandic Sheep which are around 55-65 microns and the finest fibres, like Vicuna (not a sheep, but an endangered cousin of the Alpaca that lives in the Andes), clock in around 10-14 microns.

Most fibers that used in commercially available yarn are in the 20 to 30 micron range.   This would be from your fine Merinos, generally around 18-24 microns, through your Bluefaced Leicesters (BFL) at 22-25 microns and up to your generic "wools" which are generally a mix of breeds that meet the quality desired by the mill, which will top out in the 30 micron range.

The fineness of a fiber impacts what it is best suited for.  Coarser fibers are rougher, but they make up for that by being incredibly tough and hearty, this makes them great for outer mittens and jackets .  Finer fibers are softer, they are the ones you want next to your skin and not facing the elements because they just don't fare as well against the rough surfaces of the world.

An example of different fleece staple lengths from an early 20th century textbook.

An example of different fleece staple lengths from an early 20th century textbook.

The next element to consider is the staple length, or the length of the individual fibers in a fleece.  Again there is a huge range of staple lengths around the world, which range from about 1 inch, Vicuna, up to 18 inches for the outercoat of an Icelandic sheep.  While you aren't likely to see either of these in a shop so for breeds you will see available, Merino is generally 2.5 - 4 in, BFL is usually 3-5 in and some of the "wool" you see in shops will be more like 4-8 in.

When you look at a strand of yarn it is made from hundreds and thousands of individual fibres overlapped and twisted together.  When the ends of these fibres pop free from the yarn, they can cause prick, particularly the end that was sheared.   Think about what your hair feels like just after its been cut, that blunt end can be very prickly.

The longer the staple, the fewer fibre ends there are in the yarn to pop out and make you itchy.  The other consequence of staple length is pilling.  Again, the shorter the fibre, the greater then number of ends, and the increased likelihood of pilling.

A farmer at LandLearn New South Wales shows off the staple length and crimp of this sheep's fleece.

A farmer at LandLearn New South Wales shows off the staple length and crimp of this sheep's fleece.

The third quality when considering a fiber is the crimp.  Not unlike what girls did to their hair in the 80s and early 90s, crimp is the pattern of waves within the fiber.  However in sheep this is natural and is related to the diameter of the fiber.  The more crimps per inch the bouncier the fiber, just like comparing the hair of someone with ringlet curls, against someone with just barely wavy hair.  

Now, while we discuss these different features in isolation, they generally show up in groups.  You get fibers, like Merino, that is short, fine and crimpy, and Icelandic outercoat, which is coarse, long and practically straight.  BFL falls in the middle on a whole bunch of these traits, its medium coarseness, medium length and medium crimp. 

With these fibers we are always making tradeoffs, with great softness we get pilling, with a long, straight fiber you are going to get more shine, but you are going to get a more coarse fiber. 

So when you are planning your projects, thinking about how you plan to use your finished object, and how you want it to look, this can make choosing a breed, much easier.  So the next time you are at your yarn store, or fiber festival, check to see if the breed is listed on the yarn label.  We are seeing breed-specific yarns being more and more commercially available which is wonderful. By trying out different breeds you can  feel the difference between all the unique characteristics the breeds bring along with them. 

However, this is far from the end of the story on speaking yarn, how the yarn in spun and plyed can enhance and mitigate some of the different qualities the different breeds bring to a project. 


The Fleece and Fiber Source Book - by Deborah Ronson and Carol Ekarius

The Knitter's Book of Wool by Clara Parkes