Extra-thick caramel will slide off apples from its own weight, but caramel that is too thin will not evenly coat the apples. It is easier to thin too thick caramel than it is to thicken it. Any caramel will thicken as it cools, so you will need to dip the apples while the caramel is still hot. The ideal caramel coating for an apple remains firm, yet pliable when it cools.
Transfer the caramel to a saucepan.
Heat the caramel over medium-low heat, stirring the entire time with a wooden spoon. Don't use a metal spoon because it will conduct the heat to your hand and may burn you.
Add 1 to 2 tbsp. of water to the warm caramel to thin it to the desired consistency.
Dip the apples into the caramel immediately before the sauce cools and hardens.