Soak: Cover almonds with water, cover, and let soak overnight in the refrigerator. Alternatively, soak in hot water for 1 to 2 hours.
Blend: Drain and rinse almonds, then add to a blender with 4 cups of cold water, along with any optional flavors. Blend on high for 1 to 2 minutes, or until almonds are broken down.
Strain: Strain mixture through a nut milk bag. Alternatively, lay a thin dish towel in a colander and pour mixture through. Gather up the corners and squeeze out as much of the almond milk as possible. Discard the almond pulp (or bake with it, see notes).
Adjust: Add a pinch of salt and more sweetener or flavorings as needed. Serve chilled.
Store in an airtight container in the fridge for up to 5 days.