Silk or satin: what is the difference for a pillowcase?

Silk is a natural fibre produced by the silkworm. It is made of proteins, like hair or wool. It is a raw material, in the same sense as cotton or linen.

Satin is a weave, that is, a way of interlacing threads. In a satin weave, the warp threads pass over several weft threads before going under again. The result is a surface where light reflects continuously: that is what produces the characteristic sheen.

Hence a simple consequence: “satin” says nothing about the material, and “silk” says nothing about the weave. A pillowcase can be silk woven as satin, polyester woven as satin, or silk woven some other way.

Let us compare like with like: a mulberry silk pillowcase and a polyester satin pillowcase, the two products you actually find on the shelf.

Three checks, in order of reliability.

1. Read the composition. This is the only reliable method, and it is compulsory on the label. European regulation on textile fibre names requires the composition to be stated. If it is missing or vague, walk away.

2. The temperature test. Rest your palm flat on the fabric for a few seconds. Silk stays cool, then settles at skin temperature. Polyester warms up and holds the heat.

3. Look at the reflection. Silk returns a nuanced light that shifts with the angle and changes slightly in tone. Polyester shines more uniformly and more harshly.

Burn tests circulate widely online. They are reliable but destructive, and unnecessary if the composition is correctly labelled.

Some wordings are designed to evoke silk without being silk.

• “Silk satin”: ambiguous. It may mean genuine silk woven as satin, or a satin imitating silk. Ask for the composition.
• “Synthetic silk”: a contradiction in terms. It is synthetic.
• “Silk touch”, “silky”, “silk-like”: these describe a sensation, not a material.
• “Mulberry silk”: this does denote silk from Bombyx mori. It is the most precise wording.

No, and saying so would be dishonest. Polyester satin costs five to ten times less, machine washes without precautions and survives the tumble dryer. For occasional use, a spare bed or a tight budget, it is a rational choice.

What is dishonest is selling it as silk. The difference in behaviour is real — in coolness, moisture handling and drape — and it has a price.

What is cotton satin?

Cotton woven in a satin weave. It is softer and shinier than plain-weave cotton, while keeping the properties of cotton: it absorbs moisture and holds hair more than silk does.

Can you find silk that is not woven as satin?

Yes. Crepe de chine, habotai and chiffon are silks woven differently, with matte or lightweight results. For a pillowcase, the satin weave remains the most common because it gives the smoothest surface.

How do I know whether a £15 pillowcase is silk?

It almost certainly is not. The cost of the raw material makes that price impossible for a new mulberry silk pillowcase. Check the composition.

Is silk more fragile than polyester?

It is more demanding to care for, which is not the same thing. Silk fibre is strong in tension. What damages it is heat, the enzymes in ordinary detergents, and the mechanical friction of a tumble dryer.

Weight is the other indicator that lets you compare two silks with each other: see what momme means. And for all the buying criteria, our guide to choosing a silk pillowcase.