The slaking

The quick lime, obtained from the cooking of the stones, is now ready for slaking.
This is a highly exothermic process, generated by adding water in excess to the quick lime.

Thanks to the rotation of the slaking machine, the quick lime is constantly in contact with water; it strongly reacts absorbing plenty of water, generating steam in an exothermic thermal exchange with temperatures up to 150°C (300°F). This is a chemical reaction, the hydration of the oxides, also a physical reaction takes place, changing the state from solid to a hot milky slurry called calcium hydroxide, or better known as slaked lime or lime milk.

The more water is added in the slaking process, the more efficient is the chemical reaction of oxides into hydroxides, a process that will go on slowly in time, during the long phase of seasoning.