In a large bowl, completely cover the almonds with water and soak overnight or for at least 12 hours.
When you're ready to make the almond milk, drain and rinse the almonds, discarding the soaking water. Rinse.
In a high speed blender, combine the rinsed almonds, six cups of fresh water, 3 pitted dates, 2 teaspoons vanilla extract and a pinch of salt. Blend on high for 1-2 minutes to completely grind and mix the almonds with water. It's better to let the almonds go too long than to under-mix.
Strain the almonds using a nut bag or clean tea towel, squeezing all the liquid into a large clean bowl. You don't absolutely need to use a colander, but it's a good backup. Transfer the almond milk to glass bottles and refrigerate.
Will keep, refrigerated, for 7-10 days. Shake to combine before using.