The traditional mustard is made using a technique which dates back to the 15th Century, which is why, according to connoisseurs, it is said to be of a better quality than any other mustard of its day.
Unusually for mustard, it is made using cider or beer and worked on a grindstone.
Depending on which alcohol is used (cider or beer) the end product can be mild or slightly bitter.
Mustard produced using cider and cider vinegar (the version typically found in Picardie) has a thicker consistency and is creamier, whilst those made using beer have a coarser, more 'traditional' texture and a characteristic amber-like taste.
One thing both versions have in common, though, is their subtle flavour.