For the manufacture of Cantal PDO cheese, the milk is renneted in a metal tank, or a wooden gerle in farm production, at a temperature between 86 and 93° F (30 and 34° C). The temperature is constantly monitored during the coagulation process, which lasts between half an hour and an hour. The heating is essential for the expulsion of the whey by the curd grains that retract slowly and concentrate the cheese matters of the milk.