Fill a mason jar halfway with the violet flowers, about 1/2 a cup. Pour the white vinegar over the flowers.
Cover the jar with a lid. If you're using a metal canning lid, put a square of parchment paper between the lid and the jar to prevent the metal from reacting with the vinegar.
Place the jar in a cool, dark place for 1-2 weeks.
Notes
Wild Violet Vinegar has the same shelf life as vinegar, but the color will fade with time.