Drain and rinse the soaked almonds, then pour them into a high-powered blender with 4 cups of fresh water. Blend until creamy.
Pour the blended milk into a nut milk bag, or fine mesh strainer. Squeeze well to make sure you extract all the liquid from the pulp. Save the almond pulp for another use, like making my Almond Pulp Hummus.
Return the strained milk to the blender, then add the dates, vanilla, and sea salt. Blend until the dates are completely broken down. Taste and adjust any flavoring as needed, then transfer the milk to a storage container. You can serve the milk right away or chill in the fridge until ready to use.
Homemade almond milk lasts roughly 4 days in the fridge before it can start to smell or taste "off" so only make what you will use in that time. You can freeze any leftover milk in ice cube trays to use in smoothies. Frozen milk should last for up to 3 months if you transfer the cubes into an airtight container.
You can omit the dates and sweeten with maple syrup or honey, to taste. In this case, you can blend everything together all at once, then strain it, since the liquid sweeteners don't add any additional fiber.