from http://greekfood.about.com. "Quince is one of the least used fruits in western countries, perhaps because in its natural state, it's almost always hard and astringent. However, it transforms when sweetened and cooked, and is delightful as a preserve, jelly, dessert, and when cooked with pork. This recipe yields a medium-sweet result. If you prefer sweeter preserves, increase the sugar to 4 cups"