All your Questions, Answered

What is silk?

Silk is a natural protein fibre spun by the silk caterpillar. The silk caterpillar spins a cocoon of silk to protect itself again cold, moist and insects, while transforming from small vulnerable caterpillars to fully-grown silk morphs. Silk consist of two main proteins – Sericin and Fibroin.

Why does the silk caterpillar spin the silk cocoon?

Because the silk cocoon is the caterpillars natural shield. It protects the caterpillar against cold, moist, bacteria and insects that might otherwise eat or kill it while transforming from caterpillar to morph.

Where does silk originate?

Silk originates from China. China has been cultivating silk for more then 5.000 years and is today still the world´s largest cultivator of high quality silk. Other countries such as India, Thailand, Vietnam and Brazil also cultivate silk, but have little – if nothing – to export at all.

What is Sericin?

Sericin is the protein surrounding the silk fibres (Fibroin) to make them stick together when spun into a cocoon by the silk caterpillar. Sericin is also anti-bacterial to protect the silk caterpillar against bacteria and other similar threats.

What is Fibroin?

Fibroin is the actual silk fibre. It’s the Fibroin that is used for silk yarns, silk fabrics and silk filling in silk duvets and pillows. Fibroin is also insulating and moisture absorbent.

Is all silk Mulberry silk?

No, not all silk is Mulberry silk. Only silk from the Bombyx Mori silk caterpillar is Mulberry silk. Bombyx Mori is Latin and translates to “silk caterpillar of the Mulberry tree”, because this specific silk species feed of the green leafs from the Mulberry tree.

What other silk species exist?

Many different. Other known silk species are Tussah Silk and Eri Silk. Tussah silk is another Chinese silk, also referred to as Wild Silk or Nature Silk. This silk is often used a lower quality silk, as its less expensive then Mulberry silk and also of a lower quality. Consumers should be careful not to buy Tussah silk, thinking they actually buy genuine Mulberry silk.

What does it mean that Sericin is anti-bacterial?

It means that Sericin has the natural ability to kill and inhibit the growth of bacteria. Common bacteria such as Escheria Coli and Staphylococcus Aureus are actively reduced when in perimeter of Sericin.

Does Sericin also work against dust mites?

Yes, Sericin works against dust mites as well. Accordingly to laboratory test performed by Airmid Health Group Ltd., on behalf of NordicComfort®, Sericin coasted SilkFX® fibres shows 58% reduction in living dust mites after only 8 weeks, when compared to goose down. After end test the goose down had more then double, 2x times, 134% higher amounts of dust mites, hence making goose down a least favorable choice for people with dust mite allergy.

Does all silk duvets have anti-bacterial and dust mite repellent properties?

No. In fact most silk duvets do not have anti-bacterial and dust mite repellent properties. Only silk duvets with added Sericin have the active ability to repel dust mites and inhibit the growth of bacteria. It’s therefore advisable that consumers check with their silk duvet supplier if the products are actually clinically proven dust mite repellent and anti-bacterial or if the supplier is just making unsupported sales claims.

Does NordicComfort® products have added Sericin?

Yes. All NordicComfort® products are specifically manufactured with SilkFX® filing containing enough active silk protein Sericin, to be clinically proven both anti-bacterial and actively dust mite repellent.

What is the length of a silk fibre?

On average the longest single silk fibre that can be obtained from a silk cocoon is 300 to 900 meters long. The silk cocoon itself consist of 2.000 to 3.000 meter total silk fibre, but only shorter continuous fibres can be reeled from each cocoon.

What is the difference between a long silk fibre and a short silk fibre?

Long silk fibres have 100% of silk´s benefit, whereas the short silk fibres only have little if any silk benefits at all.

So is a long silk fibre better then a short silk fibre?

Yes, a lot better! To feel a notable sleep improvement a long silk fibre must be used. Short silk fibres do not have enough fibre properties for the consumer to actually feel a benefit or sleep improvement.

Long silk fibers have enough benefit for the consumer to fell a significant benefit from the silk properties. Short fibres do not have enough properties to make a significant difference for the consumer. A genuine silk duvet should have long fibres. Short silk firbes are not as beneficial as long fibres when used in silk duvets, though the short fibrs tend to be less costly in retail price.