Learn how to grow salt crystals in many different colors, directions and shapes.When you cook up a batch of salt water, you cook salt, water, and food coloring (if you choose to use it) to an extremely high temperature. At these high temperatures, the salt remains in solution, even though much of the water has boiled away. But when the salt water begins to cool, there is more salt in solution than is normally possible. The solution is said to be supersaturated with salt. Supersaturation is an unstable state. The salt molecules will begin to crystallize back into a solid at the least provocation.