Combine the coconut and water in a saucepan and bring to a full boil over high heat. Turn off the heat, cover, and let sit for 1 hour.
Pour the coconut and water into a blender. Blend on high for 2 to 5 minutes (less time for a high powered blender like a Blendtec or Vitamix, more time for other blenders), until the texture is thick and only slightly granular (place a tea towel or other cloth over the lid of the blender, and make sure to keep your hand over the top while the blender is running).
Pour the pulp into a nut-milk bag, yogurt-cheese bag, paint-straining bag, or fine-mesh strainer suspended over a glass bowl, mason jar, or measuring cup. (If using a nut-milk bag or paint-straining bag, it is easier to handle if you place the bag inside a sieve or strainer.)
Either let the coconut milk strain out by gravity or squeeze the pulp through the nut-milk bag.
If not using immediately, store the coconut milk in a glass jar in the fridge for up to 2 weeks or in the freezer for up to 1 year. Shake well, blend, or gently warm before using.
Recipe by The Paleo Mom at https://www.thepaleomom.com/homemade-coconut-milk-revisited/