Place the almonds in a bowl and cover them with the additional water. Let them soak for 6-12 hours (beyond 12 hours they will start sprouting). Pro tip: do this before bed or before work.
Discard soaking water and rinse almonds. Add the almonds and 4 cups of filtered water to a blender. Blend on high for 60 seconds or until the almonds are well-blended.
Poor the blender ingredients through a nut milk bag (or cheesecloth or tea tea towel) over a mesh strainer into a bowl. Squeeze the bag to extract as much milk as you can.
Pour the contents of the bowl into a storage container and store in the refrigerator for up to 5 days. The almond milk will naturally separate because there are no stabilizers, so shake it well before serving.
You can use the same ratio if you would like to make more or less almond milk. It's simply one part almonds to four parts filtered water. You can also add sweeteners or flavorings, and there are countless recipes online for that. I like it just plain as it's naturally so much sweeter than store-bought almond milk.