Wash and dry the apples thoroughly and remove its stems carefully. Stick some wooden skewers in place of the apple stems and keep these apples aside. Line a baking sheet with aluminum foil and spray it with a nonstick cooking spray. Keep the baking sheet aside. In a saucepan, combine the water, sugar and corn syrup and place it on medium-high heat. Place a candy thermometer in the saucepan to check the heat. Stir it until the sugar starts to dissolve and once the mixture reaches a temperature of 250°F, leave it to cook for a while without stirring. Add the food coloring to the mixture and stir until it dissolves completely. Use a wet pastry brush to wash down the sides of the saucepan in case any crystallization occurs. Continue to cook the mixture until its temperature reaches 285°F. Then, remove from the heat and stir it to smooth it out. Pick an apple by the skewer, dip it in the candy mixture and rotate the apple to coat all the sides. Twirl the apple to remove the excess mixture and place it on the baking sheet. Repeat the same procedure with the remaining apples and allow them to cool thoroughly and enjoy them after a day.