Packaging and hardening
9 After the desired overrun is reached, the mixture is packaged and placed in freezers where the freezing process continues. The temperature falls quickly, within one or two minutes, to at least 0°F (-17°C) but ideally -15°F (-26°C). For best results, the freezing process should occur rapidly so that the mixture does not form large, coarse ice crystals but small, smooth ones. The frozen yogurt may be stored in continuous or batch freezers. In the former there is a constant flow of product into the freezer, while in the batch method, batches are prepared individually. Depending on the type of freezer and the size and shape of the package, the final hardening takes between 30 minutes to 12 hours.
Shipping
10 The containers of frozen yogurt are piled closely together inside the delivery trucks to minimize the temperature change during shipping. The vehicles are generally mechanically refrigerated at the same temperatures as in the storage facilities in the factory, about -15°F (-26°C), and not above the temperature at the retail outlet. Dry ice may be used as a refrigerant, though it risks heat-shock to the yogurt, which occurs if the temperature falls too low; the freezing point for dry ice is -109°F (-78°C). The frozen yogurt is shipped to retail outlets and food service establishments or to other manufacturers for further processing into novelties.