Dry treated down.
In this article we use the words ‘loft’ and ‘lofting’ to describe downs ability to expand after compression, and ‘fill power’ to define this lofting quality: the higher number the better.
We have been in close contact with premium quality down for more than 15 years, from when 750 fill power was the top shelf standard to current claims of 900 and beyond. Hand filling every bag and garment with down gives one an instant tactile quality assurance.
This year Nunatak introduced chemically treated moisture resistant down (hereafter: dry-down) as an option for all products. While stamped as having the same 900 fill power rating as the regular down offering, our assessment reveal distinct qualities setting these two types apart.
The short hand conclusion: Dry-down may offer a defense against moisture, but lacks in initial lofting ability. Long term lofting may not ever catch up to that of comparably rated untreated down.
The points of our findings:
Yes, dry-down will ward off moisture. There’s a difference.
When wet it’s of limited use, just like regular down – but it appear to dry much faster. Maybe the dry-down treatment limit the depth of the moisture infiltration.
900 fill power is 900 fill power, right? Not. Dry-down, in the batches we have worked with, displays less initial lofting ability compared to regular down. Aggressive ‘fluffing up’ helps, but in our production process the end result is still inferior to regular down.
Because of this, Nunatak have decided to add an extra percentage of fill to dry-down products to achieve a given temperature rating.
Dry-down products from Nunatak will be heavier than stated in the specs, and will feel denser.
After storage dry-down will take longer to loft up. Shaking, patting, massaging may be necessary.
Remove your dry-down filled bag from its stuff sack as soon as the tent is up.
On the trail take all the usual steps to limitt your dry-down product’s exposure to moisture.