In a bowl, combine the yellow and brown mustard seeds, white wine vinegar, and water. Stir well to ensure all the seeds are coated in the liquid.
Cover the bowl and let the mustard seeds soak at room temperature for at least 4 hours or overnight. This will soften the seeds and allow them to blend easily.
After the soaking period, transfer the mustard seed mixture to a blender or food processor.
Add the dry white wine, honey or maple syrup, salt, and turmeric (if using) to the blender.
Blend the mixture until it reaches your desired consistency. For a smoother texture, blend longer; for a grainier texture, blend briefly.
Taste the Dijon mustard and adjust the flavor by adding more honey, salt, or vinegar, according to your preference.
Transfer the homemade Dijon mustard to a jar or airtight container for storage.
