Soak 1 cup of the raw, shelled pistachios for at least 6 hours, or ideally overnight.
Pop the soaked pistachios into your blender, along with 3 cups of filtered water.
Blend on high speed for at least 90 seconds, or for more or less time, depending on the power of your blender. You want the pistachios to be completely shredded to a pulp.
Strain your pistachio milk using a nut milk bag or cheesecloth. You can set the pulp aside to use it later as an added source of fiber to your morning oats or baked goods.
Add salt, a sweetener or flavoring based on how you want your pistachio milk to taste.
Pour the milk in a clean glass bottle and there you have it, homemade pistachio milk!