The ingredients listed on the jar are: water, mustard seeds, vinegar, citric acid, sulphur dioxide (preservative). The reason I'm asking is, I am making a side dish of asparagus with hazelnuts and tarragon vinaigrette from the epicurious site, but when I searched for the recipe on that site and used 'vegan" as a parameter, it was not listed. The recipe ingredients are asparagus, shallots, white wine vinegar, tarragon, Dijon mustard, olive oil, hazelnuts. I'm puzzled as to why it doesn't fit the vegan parameter, so the only thing I could think is that perhaps something in the Dijon mustard disqualifies it from being vegan. Or perhaps it depends on the particular Dijon mustard you're using. Anyway, I'm getting off track. So is Dijon mustard, particularly as I have described the jar I have, vegan? I don't want to misrepresent any dish to my vegan guest.
Many thanks in advance.