Thomas Senf

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Down know-how

Down is a product of nature and is still the best insulation material there is.
Down is extremely light, durable, and an excellent insulator.

Each night, a sleeper generally loses 3 to 5 deciliters of fluid through sweating. Down has the ability to absorb this moisture and therefore ensures ideal sleeping conditions. The only disadvantage of down is its behavior when wet. If down becomes wet, it clumps together and loses insulating performance. Down should be stored dry, if possible, and aired after each use.

Careful processing of the raw material
Essential to ensure a high-quality filling. Our down partners carefully process the down using the latest technologies to ensure maximum performance, hygiene and an odour-neutral result.

Careful capture
Our best down qualities are gathered carefully by hand (no live plucking, no force-feeding!).

Stringent quality assurance
From capture to arrival in the store, the down is tested by three independent laboratories to ensure it complies with our demanding quality requirements.

Down grows in the feathers of ducks and geese and serves as insulation. "Still" air is captured in the breast and stomach area. This protects the birds from cold in winter and in summer from heat. Water birds are the only birds which have this special insulating function. Still air means that the air cannot circulate due to the small structure of the down. Thus there is no temperature adjustment between the body and the environment, the body is insulated.

One piece of down has approximately 150 branchlets, all covered in very fine hair and weighing between 1 and 4 milligrams. For our winter sleeping bags we need more than 1 million pieces of down! Unlike a feather, down has no shaft, simply a small core from which the branchlets emerge in the form of strands.

Down quality

The best raw materials come from fully-grown, well cared for birds from cold regions like Eastern Europe. The performance of the down depends on many different factors. Its origin, especially the climate, influence the down. However, the colour (white or grey) has no effect on quality.

  • Origin (climate), the best raw materials come from cold areas like: Siberia, Eastern Europe, Canada, the Pyrenees or China.
  • Holding (inside or outside)
  • Age of the bird, the basic rule is: the older a bird, the better the raw materials because:
    older birds have larger down and larger down automatically also means more fill power. Older down lasts longer, since the down branchlets grow together with the knots over several years (the down does not come apart).
  • Plucking time (moulting), in spring the down is the strongest, and a lot cleaner because at this time of year it is falling out
  • Nutrition, the more balanced the food, the better the down quality.
  • Treating (plucking, washing, sorting, drying)
  • Transport, storage, filling

These conditions alone are not enough for top quality down. Careful treatment of the raw materials (washing and sorting) is essential to ensure a good filling. The down used by Mammut is carefully cleaned in the most modern of facilities and using the best technology. It is dried and sterilised at approximately 100°C. This process ensures the best possible performance of the down, and a hygienic and odour-neutral result.

Mix ratio

Another factor which determines the down's quality is the mix ratio.
When plucking the birds, a mixture of down and feathers always comes out. Down binds more air than feathers and provides better insulation. The higher the percentage of down in a filling, the higher the insulation with the same fill weight.
Information such as "90/10" means: 100 grams of this filling contains at least 90 grams of down. A 100% down proportion is technically not possible, it would mean that the down has been hand selected. A 96/4 rating is the best.
After being plucked and washed, the feathers and down are separated over a blower. Since down is lighter than feathers, it flies higher and further - this principle makes mechanical separation possible. However, some feathers have such good aerodynamics that in spite of their higher weight they fly up as high as the down. These so-called "floaters" prevent the production of pure (100%) down fillings using machinery. Producers often like to write about an additional support function of feathers, which is not completely correct. Good down does not need feathers for stabilisation, since good down is extremely puffy. A larger proportion of feathers, however, makes the filling less sensitive to pressure and moisture.