Using clear gelatin ice cubes gives you something to chew on after the ice melts in your drink. This idea is similar to Orbitz, a discontinued soda that contained little gelatin-like orbs. You'll need unflavored gelatin to make the ice since this is the only kind of gelatin that is clear, and the gelatin needs to be granulated -- instead of using gelatin sheets -- since it has to melt and conform to the moulds in the ice cube trays.
Fill each mould in three ice cube trays one-quarter of the way full with water and sit the trays in the freezer. Leave them there until the water is frozen.
Dissolve one package of gelatin with hot water by stirring it with a spoon in a medium-sized bowl. How much hot water you will use depends upon what amount the package calls for.
Pour the dissolved gelatin into two ice cube trays. It's OK if you don't have enough gelatin to fill every mould.
Put the ice cube trays in the refrigerator and let them chill until the gelatin is firm. This may take one to two hours.
Fill the bottom of your sink with warm water.
Hold the ice cube trays with the gelatin in the water for 10 seconds. Hold the trays so that the water comes to the top rim.
Hold a tray over a cutting board and turn it upside down. Slightly twist the ends of the tray to pop the gelatin out. Repeat with the second tray.
Neatly slice each gelatin cube in half with a steak knife that has a smooth edge. When you are finished slicing, you should have approximately 30 pieces of gelatin.
Remove the three ice cube trays from the freezer and sit each piece of gelatin in an ice cube mould.
Fill a measuring cup with 2 cups of water.
Gently pour water into each mould that has a piece of gelatin until the mould is filled to the top.
Return the ice cube trays to the freezer. Let them sit in the freezer until the cubes are completely frozen.