Mulberry silk is the silk of the mulberry silkworm (Bombyx mori), a moth farmed in China for thousands of years and fed on white mulberry leaves. Its thread is finer and more even than that of wild silks: it is the silk used for pillowcases, bonnets and sleep masks. This guide explains where it comes from, how to tell it apart from polyester satin, what the momme weight means and what it changes for your hair and your sleep.
What is mulberry silk?
The mulberry silkworm is a domesticated moth, native to northern China. It is not known in the wild: it lives only on farms, in what is called sericulture. Its caterpillar, the silkworm, prefers to feed on white mulberry leaves, the ones that give the finest silk. After four moults, it encloses itself in a cocoon made of one single continuous thread.
To obtain this thread, the cocoons are plunged into hot water. The water softens the sericin, the natural gum that sticks the thread to itself. Around ten cocoons are then unwound together, and their threads bond into a single strand thanks to this gum. The thread is made mainly of fibroin, a protein; degumming then removes the sericin and gives silk its softness and sheen.
Under the microscope, the mulberry silkworm’s fibre has a triangular cross-section with rounded corners, 5 to 10 micrometres wide. These facets reflect light like a prism: this is where the pearly sheen of silk comes from, changing with the viewing angle.
Mulberry silk or wild silk: what is the difference?
Wild silks is the name given to the silks of moths other than the mulberry silkworm:
- tussah, produced by moths of the genus Antheraea, some of whose caterpillars eat oak leaves;
- eri, whose caterpillars feed on castor leaves;
- muga, a golden silk from Assam, in north-east India.
Their thread is less fine and less even. The fabric is often beige or golden, more matt, with a slight texture. Mulberry silk, on the other hand, is white, takes dye well and gives a smooth, uniform cloth. It is the one chosen for pieces that rest against the skin and hair, such as pillowcases, bonnets and masks.
Saying “mulberry” therefore tells you where the fibre comes from. The weight and the weave, for their part, decide how the piece feels and holds up.
How to tell if silk is real
Many items sold as “satin” are polyester: the word describes a weave, not a material. Three checks let you know what you have in your hands.
Read the composition label
In the European Union, a composition label is compulsory on textiles, and Regulation (EU) No 1007/2011 reserves the word “silk” for fibres produced by silk-producing insects. An item made of a single fibre may carry the words “100 %”, “pure” or “all”: “100 % silk”, “pure silk”, “all silk”.
The word “satin” on its own says nothing about the material. If the label says polyester, acetate or viscose, it is a synthetic or artificial satin. “Silk satin” or “silk charmeuse” means silk woven as satin.
Look at the sheen and feel the fabric
Silk has a pearly sheen that changes with the light and the viewing angle. Polyester shines more uniformly, with a whiter, sometimes slightly plastic gleam. To the touch, silk is soft, supple and fluid.
Silk is also said to warm to the temperature of your hand more quickly. These clues point the way, but a good polyester imitates them well: only the label and the flame give proof.
The burn test
Take a thread from an inside seam, hold it with tweezers over a sink, then bring a lighter flame close to it.
| Fibre | In the flame | Smell | Residue |
|---|---|---|---|
| Silk | burns slowly and goes out when the flame is removed | burnt hair or feathers | black ash that crumbles to powder between your fingers |
| Polyester | melts, shrinks and drips | chemical, hot plastic | hard bead, impossible to crush |
| Viscose | catches fire quickly, like paper | burnt paper | very light grey ash |
Melted polyester sticks to the skin and burns it: keep the thread away from your fingers and test a single thread, never the whole piece.
Momme: reading the weight of silk
The momme (abbreviated mm) is the unit of weight for silk fabrics. One momme is about 4.3 grams per square metre. The higher the number, the denser the fabric: it becomes more opaque, stronger and a little warmer.
| Momme | Weight | Common uses |
|---|---|---|
| 16 | 69 g/m² | scarves, linings, light masks |
| 19 | 82 g/m² | pillowcases, bonnets, sleep masks |
| 22 | 95 g/m² | thicker pillowcases and bonnets |
| 25 | 108 g/m² | premium pillowcases and sheets |
| 30 | 129 g/m² | the densest bedding |
For nightwear and bedding, you mostly find 19 and 22 momme. The momme tells you how thick the fabric is; the label tells you what fibre it is made of. Read the two together.
What mulberry silk changes at night
For your hair
On a cotton pillowcase, hair catches: every movement of your head rubs it against the fibres. On silk, it glides. When you wake up, there are fewer tangles and less frizz, and your hairstyle keeps its shape better. The difference shows most on wavy, curly or coily hair, on long hair and on coloured or straightened hair. If your hair breaks, our article breaking hair or hair shedding helps you tell the difference.
For your skin
A smooth fabric rubs the face less. When you sleep on your side, your cheek shows less of the pillowcase mark on waking than with cotton. Mulberry silk is also pleasant for skin that does not get on well with rough fabrics.
For comfort
Silk breathes. It regains about 11 % of its weight in moisture, compared with 8.5 % for cotton and 0.4 % for polyester (commercial moisture regain values from the ASTM D1909 standard). Polyester keeps moisture on its surface: a synthetic satin can therefore feel clammy when you get hot at night.
Bonnet, pillowcase or mask: which piece to choose?
- The 50 × 70 silk pillowcase protects your hair and face all night, with nothing to wear. Size 50 × 70 cm, for a rectangular pillow.
- The mulberry silk hair bonnet keeps your lengths wrapped, even if you move a lot. Its wide band and two ribbons tied at the nape adjust it to every head.
- The blackout silk eye mask blocks out the light over your eyes, even at daybreak. Flat and light, it stays in place with a gathered elastic band.
Bonnet and pillowcase work together: the bonnet keeps your hair wrapped, the pillowcase protects your face and any strands that escape. The three pieces also come together, as a trio in matching colours (black, champagne or dusty pink), from the bonnet’s product page.
Caring for mulberry silk
- Wash by hand, at 30 °C maximum, with a silk detergent or a mild shampoo. The pillowcase can go in the machine, on a silk or delicates cycle, cold, in a laundry bag.
- No fabric softener, bleach or enzyme detergent.
- Rinse in cold water, without wringing, then press the piece in a towel.
- Dry flat or on a line, in the shade: no direct sunlight, no tumble dryer.
- Iron if needed at a low temperature, on the reverse side.
Frequently asked questions about mulberry silk
What is the difference between silk and mulberry silk?
Mulberry silk is one kind of silk: the silk of the mulberry silkworm, which is farmed and fed on white mulberry leaves. So-called wild silks come from other moths and give a thread that is less fine and less even. The word “silk” on its own can mean either.
Is mulberry silk good quality?
Its thread is long, fine and even, which gives a smooth, uniform fabric: that is why it is chosen for pieces that touch the skin. The quality of an item then depends on its momme weight, its weave and how it is made.
How can you tell if silk is real?
Read the composition label: in the European Union, only a fibre from silk-producing insects may be called “silk”. If in doubt, the burn test settles it: silk burns slowly, smells of burnt hair and leaves an ash that crumbles, whereas polyester melts into a hard bead.
Is satin silk?
Not necessarily. Satin is a way of weaving that gives a shiny face and a matt reverse. It can be made of silk, but it is most often polyester. Only the label tells you.
How many momme for a pillowcase or a bonnet?
Between 19 and 22 momme, which is about 82 to 95 g/m². Below that, the fabric is lighter and more sheer; above it, the fabric is thicker and warmer.
Is silk suitable for curly hair?
Yes, it is actually on curls that the difference shows most. Curls rub less and keep their shape: the bonnet keeps them wrapped when you move, the pillowcase protects them when your head rests on it.
