It is possible to make Jello set more quickly by adding ice to the water that is called for in the preparation instructions. Chefs can also replace the recommended amount of water with an equal amount of ice to make the Jello set faster.
To make Jello set more quickly, dissolve the mix in 3/4 cup of boiling water in a medium-sized bowl. Pour 1/2 cup of cold water into a glass measuring cup. Add enough ice to the water to make it 1 1/4 cups. Pour the mixture into the gelatin, and stir until combined thoroughly. Most of the ice melts during this process, but discard any unmelted ice.
Refrigerate for 30 minutes to soft-set the Jello. Keep in refrigerator for up to 90 minutes to enjoy a soft, yet firm, Jello.