Soak your pistachio nuts for six hours, or overnight. Optionally, you can then peel the pistachios for brighter green pistachio milk - however, this isn't necessary. *
Add the soaked pistachio nuts into a high-speed processor/blender and blend on high. You want to blend the nuts down into small pieces, without blending too much to become pistachio butter.
When the nuts are ready, then add the water and blend again for about 1-2 minutes.
I use my NutraMilk processor (see post for more in info and a discount code) which allows me to drain the liquid directly into a bottle while keeping any nut meat leftovers in the jug. When using a regular blender/food processor, after blending the nuts with the water, pour the liquid into a bowl through layers of cheesecloth or a nut milk bag and squeeze out all the pistachio milk. You could also use a fine-mesh sieve and press out the leftover nut meat to drain any liquid.
This liquid can then be poured into a bottle and stored in the fridge for 3-5 days. Whenever you use some, give the bottle a good shake, and you're ready to go.
Note* If you do peel your pistachios, you can then dry out the skins and add them to porridge/smoothies for additional dietary fiber. Optional Homemade Pistachio Milk Add-Ins:
For a national sweetener, Medjool dates are wonderful
Maple Syrup or Agave Nectar are other alternative natural sweeteners.
Homemade vanilla extract - add vanilla to your homemade pistachio milk for that dessert element.
You could combine this DIY pistachio milk with other middle-eastern dessert flavors including rose water, orange blossom water, cardamom, etc.
This homemade pistachio milk makes a wonderful base for Matcha recipes