Crystallization is the (natural or artificial) process of formation of solid crystals precipitating from a solution, melt or more rarely deposited directly from a gas. We know that the final quality of ice cream an-d specially its smooth texture depends on the ice crystal size distribution an-d on the viscosity of the ice cream. So, one of the most important goals of an ice cream machine is to make ice cream with many small ice crystals, resulting in a smooth texture, an-d to preserve that ice crystal size distribution until consumption.

There are many process conditions influence the ice crystal size distribution an-d the viscosity. Such as the mix flow rate, the evaporation temperature, the cylinder pressure, the rotation speed an-d the air flow rate. During the manufacture of ice cream several steps are necessary, such as homogenization, age the mix, an-d freeze.

Homogenization can decrease the milk fat globule size to form a better emulsion an-d contribute to a smoother, creamier ice cream. Homogenization also ensures that the emulsifiers an-d stabilizers are well blended an-d evenly distributed in the ice cream mix before it is frozen.

Aging allows the milk fat to partially crystallize an-d the gives the proteins stabilizers time to hydrate. This improves the whipping properties of the mix.

The process of freeze involves freezing the mix an-d incorporating air. Air can make ice cream softer an-d creamier.