All kinds of yoghurt can not be added to the fruit, and fruit yoghurt is not available. If the temperature of milk heating is too high, it will kill the lactic acid bacteria in the yogurt and cause the fermentation to fail. If the temperature is too low, the fermentation will be slow, so that it is not hot. It is not possible to ferment the insulation of the rice cooker because the temperature of the heat preservation is too high, and the rice cooker must be powered off during the heat preservation fermentation. If you make yogurt in the winter, you can put the porcelain cup on the heating and ferment. It is best to use a porcelain cup with a lid for the fermentation vessel, and a hard plastic cup. However, if the quality of the cup is not enough, it is easily deformed during heat sterilization. The lid is very important, the lactic acid bacteria are anaerobic bacteria, and the anaerobic environment is more conducive to fermentation. It is best not to use disinfectant in the sterilization of the container, because if the washing is not clean, the lactic acid bacteria will be killed and the fermentation will fail. Heat sterilization is the safest method. Anti-milk (containing antibiotics) or reduced milk (milk reduced with milk powder) are not suitable for making yogurt ingredients. Fermented yoghurt occasionally causes fermentation failure due to unstable quality.