牛奶怎么做成酸奶

To make yogurt from milk, you can follow these steps:

1. Heat the milk to around 180°F (82°C) to kill any harmful bacteria.
2. Let the milk cool down to around 110°F (43°C).
3. Add a small amount of yogurt starter culture containing live active cultures to the milk. This can be store-bought yogurt with live cultures or a yogurt starter culture.
4. Mix the starter culture into the milk thoroughly.
5. Keep the milk mixture at a consistent temperature of around 110°F (43°C) for several hours to allow the live cultures to ferment and turn the milk into yogurt. This can be done in a yogurt maker, an oven with the light on, or using other methods to maintain a consistent temperature.
6. After several hours, the milk should have thickened and turned into yogurt. You can then refrigerate it to stop the fermentation process.

This process will turn milk into yogurt through the fermentation of live cultures.