Soft ice cream has no hardening process in the production process, and the expansion rate is 30%-60%. Generally, it can be made and sold by an ice cream machine. The expansion rate of hard ice cream is 80%- 100%, and it is hardened to facilitate packaging and transportation. Generally, a soft ice cream contains more nutrients (about 1.6 times) than a hard ice cream with the same volume. Soft ice cream without hardening will also be more creamy and mellow. In fact, the only difference between hard ice cream and soft ice cream is that hard ice cream needs to be frozen and hardened, while soft ice cream is poured directly into the cone. The hardening temperature of -30℃ to -40℃ freezes most of the water in the ice cream packaged in the package. Ice cream is quite stable when stored at -25℃, and there is no danger of ice crystal growth. However, above this temperature, ice crystal growth is possible, and the rate of crystal growth varies with the storage temperature. Admittedly, this limits the shelf life of ice cream. These fast food restaurants in McDonald's usually sell soft ice cream (it's more convenient to eat in the store)