Combine one part black mustard seeds, one part white wine vinegar, and two parts white wine with a teaspoon of salt
Let the mixture soak at room temperature for about 12 hours so the seeds hydrate and develop flavor
Blend everything with an immersion blender until smooth
Strain the mixture for a finer texture
Transfer to a glass jar and keep it in the fridge
Store for up to two months; flavor improves as it sits
