Homemade Apple Pectin

• 8 lb (4 kg) underripe apples such as Granny Smith or Pink Lady, stems removed

Cut the apples lengthwise into slices about ½ inch (12 mm) thick, retaining the seeds and cores. Place the apple slices in a pot and add 4 qt (4 l) water. Bring to a boil over medium-high heat and co