There's something almost magical about a silk cocoon. A single, unassuming oval of compressed fiber — yet inside lies one of the world's most prized natural materials, capable of being reeled into a continuous thread thousands of yards long. At KnitSilk, we work directly with silk cocoons and processed silk fibers, and in this guide we're pulling back the curtain on the entire journey: from silkworm to skein.
What Are Silk Cocoons?
Silk cocoons are the protective casings spun by Bombyx mori silkworms during their pupal stage. Each cocoon is made from a single continuous filament of raw silk — called bave — that can measure anywhere from 300 to 1,500 meters in length, depending on the silkworm variety and growing conditions.
The cocoon is held together by sericin, a natural gum protein that stiffens the filament. Before silk can be spun or woven, this sericin must be removed through a process called degumming — which reveals the soft, lustrous fiber beneath.
Types of Silk Cocoons
- Bombyx (Mulberry) Cocoons — The most common variety, producing fine, white, uniform filaments. Used in most commercial and artisan silk production.
- Tussah (Wild Silk) Cocoons — Produced by wild silkworms feeding on oak or other leaves. Naturally tan or golden in color, with a slightly coarser texture and earthy character.
- Eri Cocoons — Open-ended cocoons from Eri silkworms; the silk is spun rather than reeled, producing a softer, more matte fiber popular in sustainable fashion.
Browse all cocoon varieties in our Silk Fibers collection →
How Silk Is Reeled from Cocoons
Traditional silk reeling is a centuries-old craft that requires skill, patience, and the right conditions. Here's how it works:
- Softening: Cocoons are placed in hot water (around 90–95°C / 194–203°F) to soften the sericin and loosen the filament end.
- Finding the end: A brush or hand is used to locate the outermost filament end on each cocoon.
- Combining filaments: Because a single filament is too fine to work with alone, 5–10 cocoons are reeled simultaneously, their filaments twisted together to form a single thread of usable weight.
- Reeling: The combined thread is wound onto a reel at a controlled speed, maintaining even tension throughout.
- Degumming: The reeled silk is boiled in a mild alkaline solution to remove sericin, revealing the soft, bright fiber known as thrown silk or spun silk.
How American Fiber Artists Use Silk Cocoons
Hand Spinning
Degummed silk cocoons can be opened into mawata caps (stretched cocoon sheets) or hankies and spun directly on a drop spindle or wheel. The resulting handspun silk yarn has an incomparable luster and drape. Explore our full range of silk fibers for spinning →
Felting and Nuno Felting
Silk cocoon fibers integrate beautifully into wet felting and nuno felting projects, adding sheen and strength to wool-based pieces. Many American textile artists use silk cocoons to create surface texture and visual interest.
Natural Dyeing
Silk accepts natural dyes with exceptional vibrancy. Cocoons and degummed silk fiber are popular substrates for plant-based dyes including indigo, madder, weld, and black walnut — a growing practice in the USA's natural dye community.
Papermaking and Mixed Media
Silk cocoon fibers are used in handmade paper, bookbinding, and mixed media art for their translucency and texture. Whole cocoons are also used decoratively in wreaths, jewelry, and botanical art.
Choosing the Right Silk Cocoons for Your Project
- Color: Bright white cocoons indicate Bombyx mulberry silk — the finest and most uniform. Tan or golden cocoons are Tussah.
- Integrity: Cocoons should be firm and intact, with no holes or damage that would break the continuous filament.
- Degummed vs. raw: Raw cocoons retain their sericin stiffness; degummed cocoons are soft and ready to spin or felt. Choose based on your intended use.
- Source: Ethically sourced cocoons from established silk-producing regions (India, China, Thailand) ensure consistent quality.
At KnitSilk, our silk cocoons are sourced directly from artisan producers in India, ensuring quality and traceability from farm to fiber.
Shop KnitSilk Silk Cocoons
Ready to explore the world of raw silk fiber? Browse our collection of premium silk cocoons — perfect for spinning, felting, dyeing, and mixed media projects, shipped to all 50 US states.
Also explore: Silk Yarns | Silk Ribbons | Silk Scarves
Frequently Asked Questions
Are silk cocoons cruelty-free?
Traditional silk production involves boiling cocoons with the pupa inside. Eri silk is an exception — Eri cocoons are open-ended and the moth can emerge naturally before the fiber is harvested. If cruelty-free silk is important to you, look for Eri or "peace silk" options in our fibers collection.
Can I reel silk from cocoons at home?
Yes, with patience and the right setup. You'll need a heat source, a bowl of hot water, and a simple hand reel or even a pencil. Many fiber artists enjoy home reeling as a meditative, hands-on craft experience.
How do I degum silk cocoons at home?
Simmer cocoons in water with a small amount of mild dish soap or soda ash for 20–30 minutes. Rinse thoroughly in warm water and allow to dry. The resulting fiber will be soft, lustrous, and ready to spin or felt.
How many cocoons do I need to spin a skein of yarn?
This varies by yarn weight and spinning method. As a rough guide, approximately 50–100 degummed cocoons will yield enough fiber for a small sample skein. For a full project, plan on several hundred cocoons.
Do you ship silk cocoons to all US states?
Yes — KnitSilk ships across the continental USA, Alaska, and Hawaii. Standard and expedited shipping options are available at checkout. Shop now →