Place your soy beans in a large bowl, cover them with water, and allow them to soak overnight. Make sure you cover them with lots of water as they'll absorb a lot of water while soaking.
The next day, drain and rinse the soy beans. In batches in your , blend 2 cups of the soaked soy beans with 4 cups of filtered water. Strain the milk through a nut milk bag, ringing out all the milk until your left with just the soy bean pulp. Discard the soy bean pulp and repeat this process 1 more time until you have about 8 cups of strained soy milk in your sauce pan. (Feel free to continue this process until you use up all of the soaked soy beans!
In your saucepan, bring the soy milk up to a boil, watching carefully and stirring often. Be careful as the soy milk will foam and expand when heated so make sure it doesn't overflow!! Once the milk comes to a boil, reduce the heat to medium-low and allow the milk to cook for 15-20 minutes. Stir often and watch carefully so that it doesn't overflow!
Discard any thick foam that may form during the cooking process.
After 20 minutes, allow the milk to cool to room temperature. Scrape of the skin that forms on the top while cooling.
Optional: If wanting to make sweetened vanilla soy milk, place the milk back into your rinsed out blender (in batches if necessary) and blend in medjool dates and vanilla bean to taste.
Store the cooled soy milk in an airtight bottle in the fridge for 3-4 days.
Notes
*Prep time does not include the time it takes to soak the soy beans.