Reels one long protein filament into cloth that drapes like water and marks from a droplet.
Also called: silk blend, charmeuse, crepe de chine
The basics
What to know about silk
Silk is a protein filament spun by a silkworm to build its cocoon. Cotton and wool are short fibers twisted together into yarn. Silk instead arrives as one continuous strand hundreds of meters long. That unbroken length is why the cloth reads smooth and lustrous instead of fuzzy. The shine itself comes from the fiber's triangular cross section, which splits light the way a prism does.
Weight is measured in momme, written mm, where one momme equals about 4.3 grams per square meter. A scarf runs around 8 momme, a blouse 12 to 16, dress charmeuse about 19, and heavy shirting reaches 22 to 30. Higher momme means denser cloth that hangs better, shows through less and survives more wearings. Weave names describe the same fiber handled differently. Charmeuse is glossy on the face and matte behind. Crepe de chine uses tightly twisted yarn for a grainy surface that resists creasing. Note that satin alone names a weave and not a fiber. Most satin sold today is polyester. Look for silk stated as a percentage before paying a silk price.
Dry silk is strong for its weight. It loses roughly 20 percent of that strength once wet. That is the main reason for hand washing over a machine drum. Sunlight is worse than water. Direct light yellows and weakens silk faster than it does any other natural fiber. A silk blouse should never dry outdoors or live on a sunny rail.
Protein chemistry drives the rest of the care. Chlorine bleach and alkaline detergent dissolve the fiber, and the aluminum salts in antiperspirant break it down slowly. Silk fails first under the arms. Wash cool in a pH neutral or wool detergent, skip the wringing, roll in a towel and dry flat in shade. Press on the reverse at the lowest setting, since both steam and stray water drops leave rings on smooth weaves.
In photos
Silk on real products
See this option on different products. Open a photo for a larger view, or select the name to read its guide.
Silkworms are moth larvae raised on mulberry leaves until they spin a cocoon from a single filament secreted through the head. Each cocoon holds 600 to 900 meters of usable thread, glued together by sericin, a natural gum.
Reeling begins by softening the cocoons in hot water. Machines find the loose end of the filament and unwind several cocoons at once, twisting five to eight filaments into one yarn strong enough to survive a loom. Degumming then washes the sericin off in a mild alkaline bath, turning a stiff yellowish thread into a soft white one ready for dye.
Standard reeling kills the pupa inside the cocoon, because a hatching moth cuts the filament into short pieces. Those broken cocoons are spun into a fuzzier, less shiny yarn sold as peace or ahimsa silk, which drapes less fluidly and usually costs more.
Best for
When it works well
Blouses and evening pieces hang best in it, because the fiber is heavy for its thinness and falls in fluid folds.
Printed patterns look sharpest on silk, as protein takes dye deeply and holds the color without going chalky.
Both warm and cool rooms suit it, since silk feels cold against bare skin yet blocks air once layered under a jacket.
Linings run smoother in it, because a slick face lets a jacket slide over a knit sleeve instead of dragging on it.
Anyone willing to hand wash gains decades, as carefully kept silk outlasts most machine washed fabrics in the same closet.
