Goose down is the fluffy layer under the feathers of geese that insulates them from the cold. The material is highly sought as an insulating material for blankets, pillows, comforters, and jackets. Loft is an indicator of how good the insulation is, and high-quality is 300 and above clusters per cubic inch. Some people are allergic to down products so they must use an alternative, although the real thing is much more effective at keeping the cold at bay.
The hundreds of tiny filaments in a cluster of goose down trap air pockets, which form an insulating layer over the birds' skin. Down does the same thing when used in a jacket to keep a person warm. It also breathes quite well, wicking away moisture that can cause chilling. If compressed, goose down will fluff back up with just a quick shake. Larger and more mature birds yield more down, and variations in color do not change its insulating properties.
Goose down is carefully cleaned and separated before being graded for use in bedding, clothes, and pillows. In the US and most of Europe, cruel harvesting from live geese or ducks has been declared illegal, so down is only taken from birds that are already processed for food. Down can be white, cream, or grey, but color does not affect its warmth. Most manufacturers use white because it won't show through light-colored fabric.
Loft, or fill power, is used to measure how many cubic inches one ounce of down will fill, starting at around 300. The higher the number, the bigger the clusters and the more expensive the article will be. High-quality bedding may have a loft of over 800. Eider down comes from the seagoing eider duck and is only harvested from nests, making it exceedingly rare and costly, with a loft of nearly 900. A good goose down comforter is a great investment that can last for many years if properly cared for.
To qualify as certified goose down, the product must have at least 75% net down, not counting feathers or any other material. There are counterfeiters who manufacture down articles of clothing and bedding that either contain synthetics or use feather waste. Not only does it lack the warming properties of real goose down, feather waste often contains bacteria or mildew. Reputable providers of down goods will be open about sources and procedures used to manufacture their products.
People allergic to goose down can find alternatives on the market made from hypoallergenic synthetics that simulate its loft. These artificial materials will eventually mat and clump, leaving empty spots through which cold can travel. Wool or alpaca comforters or a cover designed to keep dust mites at bay may help allergy sufferers who want the warmth of natural bedding.