Rinse pears, apples, and grapes. Do not peel fruit.
Remove core from pears and apples. Cut fruit into 1-inch pieces.
In a medium pot, add pears, apples, grapes, raisins, cinnamon, and nutmeg.
Add apple juice and water to pot to barely cover the fruit.
Bring fruit and juice to a boil. Reduce heat and simmer for 10–15 minutes. Remove from heat.
In a colander, strain the fruit over a small bowl, reserving the liquid.
Return the liquid to the pot. Add cornstarch. Cook on low to thicken slightly. Remove from stove and let cool.
Pour thickened juice mixture over fruit and stir. Cool and serve right away. Or, store in an air-tight container for up to 1 week.