Alison I make all my own mustard. The one I use for Dijon style states after making store in a dark cool place for 3 weeks before using and then store in the fridge (the storing process lets the flavour develop. Placing the mustard in the fridge stops the flavour developing). I found this recipe, which I have just made. It is made with whole grain seeds, grape juice (I have used organic) and sesame seeds. It is the first time I have not used vinegar in my mustard. There is no indication if it should be stored to let the flavour develop before placing in the fridge or if it ever needs to go in a fridge. There is no vinegar in the mustard, so would the enzymes in the mustard seeds prevent the mustard from becoming rancid or should it go into the fridge at once. I know the ancients did not have fridges. However they use to eat vast quantaties of it.

Mark

Mark the recipe I posted was at one point produced commercially. The key to its ‘keep-ability’ was that it had a low Ph due to the acidic content of the Verjuice plus the addition of salt and the honey. (I had each batch tested though a lab). Obviously my product was stable without refrigeration as it sat on supermarket shelves. Without knowing the quantities, and/or what other ingredients you used it’s hard to comment.

However, a little science from Harold McGee! By adding moisture to the seeds it revives the seeds enzymes and allows them to liberate the pungent compounds from their storage form. Acidic liquids slow the enzymes – but also slow the later disappearance of the pungent compounds as they react with oxygen and the other substances in the mix.
Refrigeration is not mentioned.

With my recipe I found I had to soak the seeds in the liquid first before adding the other ingredients as the honey retarded the soaking process and the recipe simply failed. I have never had a batch go rancid and still have jars un-refrigerated and un-opened that are years old. I only refrigerate after opening.

How about we swap a jar or two?