First, rinse dried soybeans with water, then place them in a large bowl. Fill the bowl with enough water to cover 2-inches above the soybeans. Soak them for at least 8 hours or overnight.
The next day, drain out the water and pick out the bad soybeans.
Then, place a nut milk bag on a strainer over a large pot.
Combined soaked soybeans and water in a high-speed blender. For each cup of soaked soybeans, add about 2½ cups of water for a stronger soy flavor or 3 cups of water for a lighter aroma.
Blend the ingredients at medium speed until the soybeans turn into a fine meal, about 2-3 minutes. The color will change from translucent to white.
Pour the liquid into the nut milk bag and squeeze out as much liquid as possible. Reserve the soy pulp for another dish.
Set the pot on a stove and add the pandan leaves. Turn on the heat and get a skimmer with a bowl of water ready.
While the liquid starts to boil, foams will form. Gently scoop them out with a skimmer. Rinse the skimmer with water after each scoop to remove the foams.
After the soymilk boils, immediately turn down the heat and let it simmer for another 8-10 minutes to fully cook the soymilk. If there are more foams, continue to scoop them out.
During the last few minutes, add your favorite sweetener. When ready, remove the pandan leaves and serve warm or store in bottles once cooled.