A blue-and-white patterned mulberry silk scarf with landscape motifs draped over a wooden ring above a white pedestal, with a small green plant beside it.

What Is Mulberry Silk? How It's Made, Graded and Worn

Mulberry silk is silk spun by the domesticated silkworm, Bombyx mori, which is raised on a diet of mulberry leaves and nothing else. It is the silk behind almost every silk pillowcase, scarf and pair of silk pajamas you will find, and it is the only kind we use. This guide covers what sets it apart from other silks, how it gets from cocoon to cloth, and what the numbers on a label actually tell you.

Where the name comes from

The name describes the diet. Domesticated silkworms eat only white mulberry leaves, and because they are raised indoors, the cocoons are clean, pale and very even. Wild silks such as tussah come from different moths that feed on oak and other trees outdoors. Their cocoons are darker, their filaments shorter and less regular, and the cloth they make has a coarser, more textured hand.

That evenness is the whole point. A smooth, uniform filament makes a smooth, uniform fabric, and it takes dye evenly, which is why mulberry silk can be printed in fine detail or dyed in deep, clear colors.

From cocoon to cloth

Each cocoon is wound from a single continuous filament, often hundreds of meters long. To recover it, the cocoons are softened in warm water and the filaments from several cocoons are reeled together into one thread. That long, unbroken filament is what gives mulberry silk its glide: there are very few fiber ends sticking out of the yarn to catch on hair or skin.

Raw silk is coated in sericin, a natural gum. It is washed away in a step called degumming, which leaves fibroin, the protein that makes up the silk itself. Degummed silk is softer, more lustrous and lighter. Our step-by-step look at how mulberry silk is made goes further into reeling, weaving and finishing.

Silk is a protein fiber, closer in make-up to hair than to cotton. That matters for care: detergents with enzymes, which are designed to break down protein stains, break down silk too. The silk washing guide explains what to use instead.

Light blue 22 momme mulberry silk pillowcases
A 22 momme mulberry silk pillowcase: the same fiber, woven heavier.

Grades: what "6A" means

Raw silk is graded before it is woven. The grade reflects how long, even and clean the filament is. On the most common scale, A is better than B and C, and a number in front of the letter refines it further, so 6A is the top of the scale. In practice, a 6A label tells you the yarn was reeled from long, regular filaments with few slubs or breaks.

A grade describes the raw material, not the finished fabric. It says nothing about how heavy the cloth is or how it was woven. For more detail, see what 6A grade silk means.

Weight: what momme tells you

Momme (written mm) is the unit silk fabric is weighed in. One momme is about 4.34 grams per square meter, so a higher number means more silk in every square of cloth. Lighter weights drape and float; heavier weights feel denser, are more opaque and generally stand up better to years of washing.

  • 16 momme: light and airy. Common for scarves and entry-level pillowcases.
  • 19 momme: a middle weight used for sleepwear, robes, sleep caps and headbands.
  • 22 momme: a denser pillowcase and eye mask weight.
  • 30 momme: heavy, with a noticeably fuller hand.

Our momme guide compares each weight in more detail.

Weaves: the same fiber, different fabrics

Mulberry silk can be woven many ways, and the weave changes the look more than the fiber does. Charmeuse is a satin weave with a glossy face and a duller back; it is what most people picture when they think of a silk pillowcase. Crepe de chine has a soft, pebbled matte surface. Chiffon is sheer and light. Our guide to charmeuse silk explains why the satin weave is used so often for bedding.

This is also why "satin" and "silk" are not the same thing: satin is a weave, and it can be made from silk or from polyester. The silk vs satin pillowcase guide covers the difference.

How to tell you are buying mulberry silk

  • The label names the fiber. Look for "100% mulberry silk". "Silky", "satin" or "silk-feel" describe a finish, not a fiber.
  • It lists a momme weight. Silk is sold by weight; polyester satin rarely is.
  • It feels cool, then warms. Silk takes on body heat quickly and does not have the slick, plasticky feel of polyester.
  • It is double-sided where it matters. For a pillowcase, check whether both sides are silk or only the front panel.

Suzhou and silk

Suzhou, in the Yangtze delta, has been a center of silk weaving for more than two thousand years, and it is SuuSilk's home. Our Suzhou page tells that story; our silk scarves carry the botanical and ink-wash patterns that tradition is known for.

Common questions

Is mulberry silk real silk? Yes. It is the most common type of real silk, and the finest grades of silk come from it.

Is mulberry silk the same as charmeuse? No. Mulberry describes the fiber; charmeuse describes the weave. A charmeuse can be mulberry silk or polyester.

Does mulberry silk need special care? Cool water, a pH-neutral detergent without enzymes, no softener and no dryer. That is most of it.

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