Goose down is the ultimate insulation, providing an unparalleled warmth-to-weight ratio. It just has one fatal flaw: If it gets wet, it loses all of its insulating ability. Enter a new species of treated, highly water-resistant down.
The idea is simple. Coat each individual down cluster, plumule, and feather with a thin layer of water-repellent, or "hydrophobic," material. This keeps water from penetrating the down and causing it to collapse in a wet, useless blob. (For more on the amazing structure and properties of goose down, check out my recent Equipped column, Down Time: The Story of a Miracle Material.)
This month Sierra Designs unveiled its "DriDown" technology, which features treated goose down that, according to the company press release, "stays dry 7 times longer in the presence of rain, melting snow, or spills, maintains 98% loft after a night in a high humidity environment, and dries 33% faster when it does get wet." (Sierra Designs remains vague, however, on the precise technology and chemicals used to create DriDown, noting only that it "features a molecular level polymer" and "a proprietary application method.")
So this new form of down is not exactly waterproof, just much more water resistant than the untreated alternative. This presumably provides minimal benefit if you're wearing a down jacket in the rain for a while (it will still eventually get soaking wet), but does have huge upsides for maintaining the loft of sleeping bags in humid environments or on long winter trips, where moisture buildup can become an issue.
In June, Sierra Designs will introduce the new treated down in a line of 600-fill DriDown sleeping bags, which will retail from $199 to $299. Across the Atlantic, the UK-based gear company Berghaus also just introduced its own line of hydrophobic down, which it's incorporated into a few hybrid jackets like the Mount Asgard. If hydrophobic down lives up to the hype, I would expect most other major gear manufacturers to introduce similar products in the years ahead.
“Equipped” is an AMC Outdoors blog, written by Matt Heid.
Photo courtesy of IDFC