If you regularly drink soy milk, making it is an easy process and requires only dried soy beans, water, a piece of muslin/flour sack cloth, and a few standard kitchen tools. You do have to let the dried beans soak for several hours, but the active time involved in making the soy milk is only around 10-15 minutes.
The full instructions from culinary blog Eating Rules are presented in the video above; start by soaking 1 cup of dried soybeans for 8 hours in a cool place. Drain and rinse the soaked soybeans and place half the soybeans in a food processor or blender and puree for a minute, pouring the puree into a large pot. Repeat the process with the second half, and cook the soybean paste over medium high heat stirring frequently until you reach a boil. Turn the heat down and simmer the puree for another 8 minutes. Finally, line a colander with pressing cloth such as a piece of cotton muslin and press out all liquid using a potato masher. Using 1 cup of dried beans will produce 3.5 to 5 cups of soy milk.
The soy milk can be served hot or you can place it into clean bottles and refrigerate after it has cooled to room temperature; it will stay fresh for 3 to 5 days in your fridge. The puree left over after extracting the soy milk is called okara and is used in various recipes. I've been told that freshly made soy milk tastes a lot better than the commercial variety and it certainly costs less. If you prefer having unprocessed foods or want to store foods for emergencies it may be worth your while to make your own soy milk.
Day 25: How to Make Soy Milk [Eating Rules]