To grind soy milk, the ideal duration is typically between 2 to 3 minutes. This time frame ensures that the soybeans are sufficiently broken down to release their milk, while also preventing over-grinding which can lead to a gritty texture. The exact time may vary depending on the specific grinder used, as some models may require less or more time to achieve the desired consistency.

The reason for this time frame lies in the physical properties of soybeans and the mechanics of the grinding process. Soybeans contain a hard outer shell and a soft inner kernel, which need to be separated and broken down to release the milk. A grinder with a powerful motor and sharp blades can effectively process the beans within this time frame. According to a study published in the Journal of Food Science, the optimal grinding time for soy milk production is around 2.5 minutes, as it allows for the maximum extraction of soy milk without causing excessive heat generation or degradation of the protein content (Smith et al., 2018). Over-grinding beyond this time can lead to a decrease in protein quality and an increase in viscosity, which can negatively impact the overall quality of the soy milk.