Understanding woven wool fabric
With it’s more comfortable insulation, spark, flame and heat resistance, durability and long cultural heritage, wool remains the best fabric to use in clothing and bedding for the outdoors. After a few years making woolen products now, here’s what we know...
From the language and complex understandings of how and why fiber is graded, through to the creation of yarn that is suitable for making the sorts of fabric we use, it has been bewildering at times.
Fibre, yarn, weaving, fulling, oiling…
Let’s take a look at wool fiber and yarns, the different types of woven wool cloth, and some of the processes that wool cloth is put through to increase it’s density and usefulness, including oiling to improve some of the weather resisting performance of a finished garment.
Fiber
Fiber is the word used for the raw product of wool, after it has been taken off the sheep as a fleece. One of the first considerations for selecting wool for garments is the grade of the wool fiber. Wool grading is the sorting and classification of raw wool (fleece). It helps manufacturers choose the right type of wool for products like clothing, blankets, and carpets.
Key Factors in Wool Fiber Grading:
Fineness (Fiber Diameter):
Measured in microns and largely used to describe soft or course wool. Softer feeling wool is usually around 18 microns, courser feeling wool is somewhere over 20 microns.
Staple Length:
The length of individual wool fibers. Longer fibers are better for spinning yarn and are more desirable.
Crimp:
The natural wave or curl in the fiber. More crimp usually means softer, stretchier wool, which is easier to spin.
Colour:
White wool is most valuable because it can be dyed easily. Stains, yellowing, or discoloration is downgraded.
Strength:
Strong fibers resist breakage during processing. Weakened wool (due to poor nutrition, stress, etc.) is downgraded.
Cleanliness (Yield):
Wool contains grease, dirt, vegitation. Yield = the percentage of clean wool after scouring (washing). Higher yield = higher grade.
Wool Grades to the Micron System
Ultrafine - ≤ 16.5µm (microns) - Luxury apparel (e.g. fine suiting, scarves)
Superfine - 16.6 – 18.5µm - High-end garments, next-to-skin wear
Fine - 18.6 – 20.5µm - Knitwear, base layers
Medium Fine - 20.6 – 22.5µm - Jumpers, socks, woven garments
Medium - 22.6 – 24.5µm - Blankets, heavier garments
Strong (Broad) - 24.6 – 27.5µm - Rugs, upholstery, outerwear
Very Strong 27.6 – 32.0µm - Carpet, insulation, industrial use
Coarse - > 32.0µm - Felting, stuffing, non-textile uses
A typical fiber that Peak Oil Company seeks would come from a Corriedale, Romney, or Crossbred Merino sheep, capable of producing a fine to medium fleece of fiber measuring 18-24 microns. Such fiber can be used to create a strong and consistent yarn, suitable for weaving a durable, dense and soft fabric that can withstand fulling (felting).
Yarn
Wool fiber is spun (twisted) into a string we call yarn. Yarn for the sorts of fabric we seek should be fine, strong, uniform, and tightly spun. The yarn must withstand fulling (felting) after it has been woven into a cloth. The yarn type we seek is a medium weight, 2 ply worsted yarn - where the long fibers are combed and aligned before being tightly spun.
Weave
Plain Weave
Plain weave is the simplest weave of over one, under one. It produces a smooth, firm cloth that is typically used in lightweight garments and scarves.
Twill Weaves
Twill weave appears like diagonal ribs in the weave pattern of the fabric, because yarn is passed over two, then under one. It produces a durable cloth that flexibly drapes over our bodies better than plain weave. Examples of twill weave wool include Gabardine, Serge and Tweed. Cloth woven in twill is typically used to make suits, trousers, jackets and outerwear.
Fulling woven wool
Many woven wool fabrics are put through a process called fulling, which is like felting, to increase the density, durability and insulation qualities of the cloth. Different names are given to different levels of fulling.
Flannel (lightly fulled and brushed)
Where a twill or plain weave wool cloth is lightly fulled (felted) and brushed to feel softer and slightly fuzzy. Flannel wool is often used in shirts, lightweight suits, trousers and linings. It is prone to pilling and is less durable.
Melton and Loden (heavily fulled / felted)
A densely woven twill or plain weave that has been heavily fulled (felted) and brushed to produce a very thick, smooth, almost felt-like cloth. Melton is used in heavy coats, outerwear, blankets and is heavier, bulkier and so warmer, more weather resistant and more durable.
Boiled Wool
Knitted or loosely woven wool that is then shrunk and fulled, to producing a warm and stretchy garment or cloth that is softer and more flexible than Melton. It is usually used in hooded garments, looser ponchos, mittens with stretch, layered jackets but is prone to stretch and sag in high-stress points like knees or elbows and is less generally durable.
Full wool yourself
Fulling wool yourself is a rewarding process, but it requires planning and experimentation to get consistent results.
Fulling is shrinking and matting a woven wool fabric using heat, moisture, and agitation to make it denser, warmer, and more wind/water resistant. This is why it is often referred to as felting. The main difference between fulling and felting is that fulling is done to a woven wool fabric, whereas felting is done to wool fiber, such as needle felting or wet felting, which are used for making non-woven textiles.
Start with a plain or twill weave 100% wool that is minimally finished (fuzzy). Fine soft wool felts quickly, but coarser fibers may offer more structure post-felting. Start with 10–20% more yardage than needed, as fulling shrinks fabric by 10–30%.
In a top loading washing machine use hot water and a bit of soap (pH helps open fibers). Wash on a longer cycle with high agitation and add towels or jeans to increase friction. Rinse with cold water to shock and lock fibers. You should be able to see that this is how we accidentally shrink and destroy your woolens normally! Dry flat under tension to avoid distortions. Press with steam to smooth and shape. Optionally brush the surface for a more Melton-like nap.
Oiling fulled wool cloth
The natural oil found in raw sheep wool is called lanolin and it is an excellent ingredient for repelling water. Ideally, it is good for wool garments to retain lanolin if you're likely to be using that garment in the outdoors. Sámi wool garments, naval coats, and Icelandic fishermen’s gear all historically retained or reapplied oils after finishing. Some modern makers of wool sleeping bags and bushcraft coats do this for durability and natural weatherproofing.
Wool fibre that retains lanolin is often called “greasy wool” because it feels very greasy to touch. But cleaning and processing the fibre into yarn, and then weaving and felting/fulling the woven cloth involves combing, hot water and soap. Hot water and soap inevitably strips the wool of its lanolin with a melting point for the oil bring ~38–44°C. Unless you use very gentle, cold methods (which would reduce felting effectiveness), you'll lose much of the natural lanolin in the process.
So it's often better to reapply the lanolin after the felted wool garment has been made. This has the added benefit of keeping the greasy feel to the outside of the garment - where its needed, keeping the inside grease free, comfortable and breathable.
You can reapply lanolin to wool fabric either by bath or spraying. Spraying is better for a more targeted and one sided use.
DIY Lanolin Spray Recipe
Ingredients:
1 tsp anhydrous lanolin
1/2 tsp liquid castile soap (or Eucalan)
250 ml hot water
Instructions:
Melt lanolin in a heatproof cup.
Add soap and stir well to emulsify.
Slowly add hot water while stirring.
Pour into spray bottle and shake before use.
Spray lightly and evenly onto garments.
Let cure 24 hours.
