Updated: Oct 19, 2019
Mustard seed has marked the oldest Mediterranean cultures. The Egyptians, Greeks and Romans used it already to enhance meat and fish dishes. They crushed the seed and mixed it with the food.
It is probably the Romans who imported to Gaul the use of table mustard. Then, later, the good King Charlemagne recommended cultivating this spice in all its states-general and the gardens bordering the monasteries in the suburbs of Paris.
The origin of the word "mustard", comes from two Latin words (mustum ardens) which meant "the hot must" because at all times the mustard was prepared with must (unfermented grape juice).
Others refer to the time of Duke Philip the Bold, Duke of Burgundy, who in 1382 granted the city of Dijon various privileges and especially that of carrying his weapons with his motto: "Moult me tarde" ... but this origin seems unlikely.
This explanation demonstrates at least one thing is that Dijon was already very famous for its mustard in the fourteenth century.
Two centuries later, the vinegar and mustard corporation of the city of Dijon was born. Their imagination has allowed the different types of French Mustards that we know today.
It was "Jean Naigeon", a Dijon’s craftsman, who in the year 1752, substituted verjus for vinegar in his mustard recipe (verjus is the juice of unripe wine grapes). This recipe made the fame of Dijon mustard.
Unfortunately the species of grapes (Bourdelas) used became victim of a disease and disappeared for good. It was replaced with verjus of other grape types but did not have the same particular flavor as the Bourdelas grape. Today the verjus (expensive) is not used any-more; it has been replaced by a mixture of vinegar and white wine.
Dijon mustard is basically made with brown mustard seeds (Brassica juncea) and verjus (salt, pepper).
Certain additions like water, wine, vinegar, spices and other ingredients are allowed as defined in the Decree n° 2000-658 relative to A.O.C (Burgundy & Dijon) mustards.
Mustard seeds immersed in verjus (vinegar, white wine) ferment over time. The mustard seed contains sinigrinase which, hydrolysed in contact with the liquid by an enzyme (myrosynase), produces the essential oils which gives the mustard the strong spicy taste. This is synaptic fermentation
French mustard fabricants are still using millstone systems (little elevation of temperature) to produce mustard; as the essential oils are very volatile and sensible to heat.