Step 1: Prepare your apples by washing them thoroughly with hot water and scrubbing to remove any wax. Dry them completely. Insert a wooden stick firmly into the stem end of each apple, pushing about halfway through.
Step 2: Line a baking sheet with parchment paper or a silicone mat and lightly grease it. Set aside.
Step 3: In a heavy-bottomed 3-4 quart saucepan, combine the granulated sugar, light corn syrup, and water. Stir gently with a wooden spoon or heat-proof spatula until the sugar is moistened.
Step 4: Attach a candy thermometer to the side of the pan, ensuring the tip does not touch the bottom. Place the saucepan over medium-high heat and bring the mixture to a rolling boil without stirring.
Step 5: Continue to boil the mixture, watching the thermometer carefully, until it reaches exactly 300°F (149°C) – the hard crack stage. This will take approximately 15-20 minutes. Do not stir during this boiling process.
Step 6: Immediately remove the saucepan from the heat. Carefully (the steam will be very hot!) stir in the red gel food coloring until it is evenly distributed and the candy is a vibrant red. Work quickly.
Step 7: Tilt the saucepan slightly to pool the candy mixture. Holding an apple by its stick, quickly dip it into the hot candy, rotating to coat the entire apple evenly. Ensure the coating covers almost all of the apple, leaving a small space near the stick.
Step 8: Lift the apple from the candy, allowing any excess to drip back into the pan. You can gently twirl the apple or lightly tap the stick against the edge of the pan to remove drips.
Step 9: Place the coated apple on the prepared baking sheet. Repeat quickly with the remaining apples. If the candy thickens too much, you can gently warm it over very low heat for a few seconds to make it more dippable, but be careful not to overcook.
Step 10: Allow the candy apples to cool completely at room temperature for at least 30-60 minutes, or until the candy shell is firm and hard to the touch. Avoid refrigeration, as it can cause condensation and make the candy sticky. Enjoy!