There are two sources of mixed milk powder, one is imported milk powder, and the quality of international brands is guaranteed; Second, some dairy processing plants collect more milk in the milk production season to make off-season milk powder, and the quality is average. The fermentation process of milk is very simple. Sweetness means that the fermentation time is short and the lactic acid bacteria fermentation is incomplete, which does not mean that there is a problem with the product quality (of course, acidity is also an indicator of yogurt). The taste of flour is made of reconstituted milk, which is more obvious in stirred yogurt. I forgot to say that the milk fermentation process can be divided into two types: coagulation type and stirring type according to the first canning and then fermentation or first fermentation and then canning. The solidified type looks sticky like old yogurt, and the stirred type tastes thinner, but it can be made into various fruity yogurts by re-ingredients and adding various jams. Generally speaking, the strains used to stir yogurt are better. Making yogurt at home is very simple, just control the fermentation temperature. It is recommended to refrigerate after fermentation, and the taste is better!