What wool fill is

Wool pillow fill is scoured sheep fleece made into layers of carded batting, into small balls, or left as loose fibre, and those three constructions sleep differently enough to be treated as separate products.

What does scouring actually do?

It washes grease, suint and vegetable matter out of raw fleece, and how far it goes determines what remains.

Residual lanolin is not a defect. It is a processing choice, and it has consequences for scent, for moisture behaviour and for how the fill ages.

Woolmark puts the grease, sweat salts and dirt in shorn wool at around 35% to 40% of the fleece's weight (Woolmark), and a wool-testing bulletin says scours usually aim to leave 0.5% or less grease on the washed fibre (SGS). Several pillow sellers say about 1% of the lanolin is kept without saying what that 1% is a share of. The guide on what scouring removes sets those figures side by side.

What gives wool its spring?

Crimp, the natural wave along each fibre, holds the fibres apart, so a mass of wool pushes back when a head presses into it.

Wool judges read crimp as a clue to fineness: locks with more crimps per inch tend to be finer (SDSU Extension). Fineness itself is given in microns, and the USDA sets its 64s grade at 20.60 to 22.04 microns (USDA AMS). The guides on crimp and on micron, grade and staple explain both.

How do batting, balls and loose fill differ?

Batting is carded wool built up in layers and usually sewn shut. Balls and loose fill sit behind a zipper, so the height can be changed.

Batting sellers put the early settling in writing. Holy Lamb says pillows made with wool layers may settle 15-30% in the first few months (Holy Lamb Organics), and Shepherd's Dream expects 30% to 40% compression over the first six months (Shepherd’s Dream). For its zippered pillow, Holy Lamb sells extra wool puffs in 3- and 6-oz bags (Holy Lamb Organics). The guide to batting, balls and shredded wool compares all three.

Does organic certification change the fibre?

No. It describes husbandry and processing inputs, not the mechanical behaviour of the wool itself.

None of the sources read for this site suggests that a certificate changes how a fibre of a given micron behaves under a head. What the label does prove, and how often it covers only the cotton case, is the subject of the guide on what makes a wool bed pillow organic.