4. Melt 5-6 cups duck fat in a saucepan over low heat. When the fat reaches 200°, barely simmering, add duck and simmer, completely submerged, until tender, about 2 hours. Remove from heat, cool, and refrigerate the duck, completely immersed in the duck fat, in a clean container. The flavor will improve for a week; the confit will keep for at least a month.