View Goose Down
The fine feathers plucked from chest area of a plump waterfowl. Goose down is what fills our sleeping bags. Down is very good at keeping you warm, but if you can’t keep the bag dry then it cannot do it’s job well.
Ducks and Geese are the main source of down, but just what is down! Alright we are getting to it. Like all genuine birds these plump waterfowl have several types of feather. Some help keep them up in the air, some keep them warm, some keep them streamlined when floating about on the water and others well they don’t even know what they are themselves.
These are the most important feathers that a bird owns, without them they would fly as well as a dog, they would also need a lot more of the small fluffy downy ones as they would be walking out of the artic. Because they are so good at helping a bird fly, they are not much use as insulation.
These are the little critters that don’t know what they are. They look like feathers on the top portion and then turn in to loose fluffy feathers towards the base of their stems.
Down feathers are small with no interlocking barbules and rachis that are soft and poorly developed. They grow continuously and never moult and lie under the contour feathers. On the majority of birds they are found on the breast and belly. This is the mythical down.
Quantity of fill
The more down you have in a bag the warmer it is, this is known as the Fill weight, (don’t confuse this with “Fill power” which is a measure of how good the down is: not all down is the same) This means that you can have a sleeping bag which either has:
Low fill power and Higher Fill weight (cheaper but bulkier and heavier)
Low fill weight and high Fill power (more expensive but more compact and lighter)
There is no substitute for good quality down and the easiest way to measure this is to check out its Fill Power, the higher the number the better it is. But attention, just because some thing has an extra hundred here and there doesn’t mean it substantially better.
The numbers game
In the last few years several brands have developed 900 fill power. Be aware, evolution doesn’t happen so fast, they haven’t developed Superduck. What they have done is get a bit better at sorting the pure down from the feathers and a awful lot better at getting the best test results from the same down quality they used before.
The old fashioned way of selling sleeping bags was based on season rating. You go into the shop tell the sales guy when you are going to use the bag and you walk out the shop a happy bunny.
1 season = Summer
2 season = late Spring, early Autumn
3 season = Spring, Summer and Autumn
4 season = Winter
5 Season = Some where really really cold
Well it was a easy system to understand but some what open to abuse. Today we all have to be a bit more careful and there are now two systems emerging as the most commonly used in the UK, we won’t attempt to explain the systems as the guys from Ajungilak have produced a fantastic document which if you want to know more is well worth reading. The ‘Sleep well’ technical document is essential for all gear freaks.