A machine can be used as a yogurt maker, warm appliance and refrigerator in the household, consists of: a thermally insulated fermentation compartment, a thermocouple or a temperature sensor, a thermoelectric assembly, a selective function switch, a safety door switch, a controller, and at least one milk container. Such units, controlled through pre-programmed cycles, can perform a variety of tasks: It is able to automatically prepare yogurt by distributing transformation culture into milk following the gradual warming, incubation and natural cooling processes; fermentation time is automatically set according to the load production and environment temperature; afterwards, maintain yogurt with cold temperature for extended periods of time.