Silk yarn: what the fibre does in a skein

Silk has been traded along whole continents for one simple reason: no other fibre combines shine, strength and coolness like it. In knitting, silk does three jobs at once. It gives fabric a fluid drape, keeps colours deep and luminous, and feels cool against the skin even in high summer. If you know you want that, start in the silk category; if you want to understand the differences first, stay here.

What silk brings to your knitting

A silk thread is smooth, long and strong: fabric knit from it hardly pills, hangs well and survives years of wear. Silk also manages moisture well. It absorbs it while feeling dry, which is why a silk blouse is pleasant when the weather flips between warm and cold.

Like every natural fibre it is not stretchy, so silk fabric grows with gravity. That suits shawls, tops and anything meant to flow, less so ribs that must snap back. And unlike wool, silk does not trap heat aggressively: it cools when it is warm and holds a gentle layer of warmth when it is not. If summer knitting is your season, the summer yarn guide shows which fibres work beside silk.

Mulberry, tussah, bourette, eri: four kinds of silk

Not all silk is the same yarn. Mulberry silk is the classic: cocoons of cultivated silkworms fed only mulberry leaves, reeled into long, even, glossy fibres. It is the finest and smoothest silk available.

Tussah, or wild silk, comes from wild oak-feeding silkworms that live and spin in nature. Their fibre is slightly coarser, naturally cream to honey-coloured, matte with a quiet glow. Because the moth leaves the cocoon before harvesting, tussah counts as a peace silk.

Bourette silk is spun from the cocoon leftovers that remain after the long mulberry fibres have been reeled off: short fibres, little irregularities, a soft nep here and there. It is matte, textured, and full of sericin, the natural silk gum traditionally valued for being kind to sensitive skin. Its faint scent washes out after a few baths.

Eri silk, rarest of the four, comes from cassava-fed eri silkworms. Like tussah it is a peace silk, with a soft wool-like character rather than a shine.

Two pure-silk lines worth a closer look

BC Garn Soft Silk is 100% bourette silk at its most likeable: fingering weight, 350 m on a 100 g hank, knit on 3-3.5 mm needles. It looks like linen at first glance, matte and a little rustic, but it knits up soft and gets softer with washing. It works for summer tops as well as for transition-season pieces, and its natural dyes give a calm, plant-toned palette.

BC Garn Tussah Tweed takes wild tussah silk and adds the classic tweed nep: little dots of colour scattered through a natural base. It is a light fingering, 250 m on 50 g, on 2.5-3 mm needles. Fresh off the hank it feels firm, which is typical for tussah, and it softens noticeably after the first hand wash. Silk's stability makes this line equally popular with machine knitters and weavers.

Silk in blends

In blends, silk adds strength and sheen to soft fibres and keeps drape fluid. A clear example is Kremke TRILOGY: 54% baby alpaca wrapped with 22% super kid mohair around a core of 24% fine mulberry silk, at a generous 800 m per 100 g. It ships undyed, natural white, made for hand-dyers and just as lovely knit as it comes. The most famous silk partnership of all is mohair-silk: the mohair and mohair-silk guide walks through those lines in depth.

Caring for silk yarn

Silk asks for gentle treatment: hand wash in cold water with a mild soap, dry flat, iron on low if at all. Natural-dyed bourette silk may release a little colour in the first bath. That is surplus dye, not fading. Always let the ball band have the last word.

Did not find the silk yarn you were looking for? Our yarn substitute finder matches alternatives by composition and yardage.