To open a coconut: Heat the oven to 375ºF. Place the coconut onto a folded towel set in a large bowl. Find the 3 eyes on one end of the coconut and, using a nail or screwdriver and hammer or meat mallet, hammer holes into 2 of the eyes. Turn the coconut upside down over a container and drain the water from the coconut. Store the water in an airtight container in the refrigerator for up to a week. Place the coconut onto a half-sheet pan and bake in the oven for 15 minutes. Remove from the oven. The coconut should have cracked in several places. Using an oyster knife or other dull blade, separate the hard shell from the brown husk. Using a serrated vegetable peeler, peel the brown husk from the coconut meat. Rinse the coconut meat under cool water and pat dry. Break the meat into 2 to 3-inch pieces. With the grater disk attached to a food processor, grate the coconut.
Place 1/3 cup of the shredded coconut into a 1-cup glass jar with lid and pour the vodka over it. Seal and shake to combine. Place in a cool dark place for 5 to 7 days, shaking to combine every day. Strain the coconut and discard. Return the vodka to a clean jar or to its original bottle and store in a cool place for up to 1 year. Reserve the remaining coconut for another use.