Put cumquats into a large saucepan and just cover with water. Bring to a boil, then simmer over low heat until fruit has softened, about 30 minutes. Strain and set aside. Bring remaining ingredients to a gentle boil in a large non-reactive pan, stirring until sugar has dissolved. Add cumquats and simmer for 20 minutes. Cover pan with a lid and stand for 12 hours or overnight.