The maturation process involves keeping the mixture at a temperature of about 4 to 5°C (39°F–41°F) under constant agitation. This phase allows the mixture to thicken and facilitates the incorporation of air during the subsequent churning process. It also enables the water in the mixture to be better absorbed by the solid components.
During proper maturation, proteins are brought to a state where they absorb free water as hydration water. Complete hydration of solids—especially milk proteins, eggs, and compound ingredients—is critical to achieving a fine, easily spreadable texture. Proper hydration during maturation prevents the formation of large ice crystals, which would otherwise result in a coarse, less pleasant product. At the same time, fats harden and crystallize, which helps the gelato incorporate air more effectively during churning.
Until a few years ago, it was believed that the mixture needed to mature for 48 to 72 hours, making this step quite time-consuming. Thanks to new stabilizer formulations, this time has now been reduced to 4 to 6 hours. However, for producing an excellent artisanal gelato with consistently high quality, it remains a good practice to prepare the mixture in the pasteurizer the evening before and transfer it to the maturator overnight. This allows a longer, more substantial maturation period of 12 to 14 hours.
Next comes churning (or gelation), the phase where the mixture transitions from liquid to solid. This transformation is driven by three factors: agitation, cooling, and the introduction of air. Churning is undoubtedly one of the most important steps in gelato production, as it largely determines the product’s quality and yield.
What happens during churning? The gelato mixture freezes as water transitions to ice. The mixture is cooled rapidly from about 4 to 6°C (39°F–43°F) down to around -15°C (5°F) under constant agitation and air incorporation. This rapid freezing prevents the formation of large ice crystals, resulting in a smoother and less grainy texture. Continuous stirring also helps trap air, increasing the volume and contributing to the gelato’s light, creamy consistency.