Wash, peel, and core apples. Cut into slices about 1/2-inch wide. Place slices in cold water with ascorbic acid to prevent browning.
Place 6 cups at a time of fresh sliced apples in about 1 gallon of boiling water. Boil for 1 minute after the water returns to a boil. Drain.
Keep warm apple slices in a covered bowl or pot. Repeat for remaining apples.
Combine sugar, Clear Jel, cinnamon, nutmeg, apple juice, and water in a large pot. If desired, food coloring may also be added.
Stir and cook on medium high heat until mixture thickens and begins to bubble. Add lemon juice and boil 1 minute, stirring constantly.
Fold in drained apple slices and immediately fill jars, leaving 1 inch headspace. Fit jars with lids and hand-tighten the ring bands.
Cover jars with at least 1 inch of boiling water in canner and process for recommended time according to altitude: 0-1000 ft - 25 min, 1001-3000 ft - 30 min, 3001-6000 ft - 35 min, above 6000 ft - 40 min.
Turn off heat. Remove jars carefully and place them onto a towel or cooling rack.
Let the jars sit undisturbed while they cool, 12 to 24 hours.
Remove ring bands from sealed jars. Label and store in a cool, dry, dark place. Use within a year.
Notes
If you don't have access to Clear Jel, the thickener recommended now, you can skip the thickener all together and can the apple pie filling without the Clear Jel. When you are ready to use the canned pie filling, just add a regular thickener when you make the pie. For example, stir in about 1-2 tablespoons of flour at baking time for a 9-inch pie.
To Freeze: Let apple mixture cool. Spoon mixture into large resealable freezer bags, seal removing as much air as possible, and freeze. About 4 cups of apple mixture will fill one standard size pie.