From Cocoon to Cloth

Here’s a closer look at the reeling and spinning technique that transforms a cocoon into silk thread.

We’re back with another post in this behind-the-scenes blog series on the silk production process. Members of the Uwila Warrior team took a special trip to Asia to get a closer look at the way our silk is sourced. If you haven’t read our first post, make sure to check it out!

Our last post focused on the care and cultivation of Bombyz mori, the domesticated silkworm species that creates the components needed to make silk via the centuries-old sericulture process.

In this post, we’ll look at the intricate techniques that transform five-day-aged silkworm cocoons into the raw silk thread we use to spin our soft and luxurious silk fabrics. We’ll go through sorting, cooking, silk reeling and spinning, and the packaging and bundling of filament—plus every quality control measure along the way.

Interestingly, each cocoon produces one extremely long and very thin single, continuous silk filament that can reach up to 3,000 feet (or 900 meters) in length. Keep reading to learn more!

Step 1: Sorting

These cocoons are being sorted.

Cocoons are dried and transferred to the reeling facility where they are examined closely and sorted manually for quality control and assurance. Any cocoons that appear damaged are discarded—this step ensures that the strongest filaments are sourced. Around five percent are discarded in this step.

Step 2: Cooking

After being graded and sorted, cocoons are loaded into a large funnel with hot water to rehydrate and soften it in preparation for reeling. Only water is used in this step—no softeners or detergents necessary. Cocoons are washed several times, starting in 30℃ water and gradually moving up to 100℃ for 11 minutes.

Cocoons cooking in hot water 

Step 3: Shaking-Out Machine

Following the cooking phase, cocoons enter the Yarn Shaking Out Machine—which does exactly what it sounds like. The machine brushes the exterior layers of the cocoons to isolate the filament. The outer layer of the cocoon will be spun next.

Step 4: Cocoon Spinning

What remains of the cocoons are then transferred to the spinning area. Batches of 8-9 cocoons are spun together to create yarn. It takes around 300 fresh cocoons to make 180-gram reels. The silk is quite delicate and must be hydrated at each step to prevent filament from breaking.

A first glimpse of thread!

Step 5: Reeling

Silk reels await a hydrating shower.

This step describes the transfer of silk filament to a spool where it can be stored safely. It looks very much like film reels used in movies! At every stage, the silk filament is hydrated to prevent breakage. 

Step 6: Packaging the Filament

The final stage preps the thread for its sale—and then its eventual transformation into the silk fabric we imagine when we think of silk. The thread is spun and bundled together in a standardized way. The bundles are called Hanks—just like Tom. 

These blocky white stripes are all silk filaments.

After a final quality inspection, the silk is transferred from the hanks and packaged in paper. 

Fun Fact

To wrap things up, we’ll share some fun facts we’ve learned along the way. It takes a whopping 234 cocoons to create a single pair of Uwila Warrior briefs! And five kilograms of filament—or one full package—makes 80 pairs of briefs.

Stay tuned for another blog post on our silk partners’ organic farming practices! We are very proud to say that the Uwila Warrior factory has received a USDA Organic certification.