From Cookipedia(Redirected from Duck fat)
Goose fat is often separated and stored for use on its own. It can be used as a substitute for butter and has a low proportion of saturated fatty acids compared to other animal fats such as butter and lard, although the flavour can be slightly "gamey". Potatoes cooked in this fat are highly regarded by some. The fat keeps well in the refrigerator.
In canned and bottled form it will keep for years.
For those requiring further enlightenment on this subject, try the Goose Fat Information Service!
Ultimate roast potatoes
Preheat the oven to Gas Mark 7 or 220°C. Par boil potatoes for 8-10 minutes; drain and then put back into the pan, shaking to roughen the edges. Measure 1 tablespoon of Goose Fat for every 450g potatoes into a roasting tray and heat until the fat is smoking.