Gelatin has different purposes depending on the type of cheesecake you're making. For no-bake cheesecakes, the gelatin is used to help the mixture set up when the cake is refrigerated. For traditionally baked cheesecakes, the gelatin is added to the batter to help give the cake a little more body and hold together when sliced. In either case, the gelatin should be dissolved prior to being added to the cheesecake batter.
Pour the water into a saucepan.
Sprinkle a light layer of gelatin onto the surface of the water. Allow the water to absorb the gelatin before adding a second layer of gelatin. Continue until all the gelatin is used. Let stand five minutes.
Stir the gelatin over low heat until it completely dissolves.
Cool the gelatin mixture slightly before adding to the cheesecake batter.