Dressed up for the table with fresh berries and mint sprigs, seltzer and syrupy raspberry vinegar make a thirst-quenching combination.
Bring vinegar and sugar to a boil in a small saucepan over medium heat. Boil, stirring occasionally, until sugar is dissolved, about 1 minute. Set syrup aside to cool. Put syrup in a pitcher; stir in seltzer, add ice, and serve.