Generally speaking, we tend to think of goose down clusters being bigger and cleaner than duck down clusters, and thus consider goose down to be of higher quality than duck down. Aside from this reason, is there any other method that can be used to prove the superior quality of goose down? Based on the excellent washing technology currently utilized in Taiwan, all goose and duck down can be thoroughly cleaned to remove excess surface oil, fat, and dirt. After drying and sterilization at high temperature during the last stages of the production process, almost all products produced in Taiwan that use down are clean for use.
The only difference is that, in foreign countries, geese normally require a greater number of days for breeding than ducks and goose down is usually larger and thus is more expensive. Therefore, suppliers perform pre-processure to ensure that goose down materials are cleaner.
The tail gland of waterfowl secretes different oils in different seasons which they then spread over their feathers. These oils are moisture resistant, prevent bacterial decomposition, and act as lubricants to prevent breakage. Using specialized analysis equipment (gas chromatography mass spectrometry) to analyze the oils on the surface of goose or duck down, we can see that these oils can be divided into three types: cholesterol, fatty acid, and wax (aliphatic alcohol+fatty acids).
Early studies conducted by Kwong Lung found that the major ingredients of the oils on the surface of duck down are fatty acids, whereas waxes are the major ingredients on the surface of goose down. Fatty acids can be easily decomposed by microorganisms and lead to bacterial growth which subsequently causes a breakdown of the down fibers.
Due to the fact that waxes provide excellent protection to down structure without odor, and because the three-dimensional structure of goose down is large and fluffy, this naturally results in superior quality.
In conclusion, there are many good reasons why goose down is relatively more expensive. It is of a higher quality and is relatively fluffier, making it more conducive as a natural filler for use in thermal insulation.