Place the pineapple pieces and the vodka or rum in a large nonreactive metal or glass container with a lid. Cover and let sit for one week in the refrigerator, stirring it once a day.
Strain the liquid through a fine-mesh sieve set over a bowl, allowing the fruit to sit in the strainer for 30 minutes so as to get all the liquid. Discard the fruit and funnel the infusion back into the original bottle and label. The infusion will keep for two weeks in the refrigerator.
To serve, pour 3 ½ ounces of the pineapple infusion into a shaker and shake with ice until chilled. Strain into a chilled coupe glass and garnish with a pineapple wedge.