This homemade whole grain mustard is a nice balance of acid, heat and depth. It is by no means over the top in it's heat. I would say it's about on par with many 'spicy' store bought German mustards. I love this recipe for it's simplicity of method and it's traditional flavor. I have lots of specialty mustards, but this one is my go to.
We make all our own mustard, mayonnaise, salad dressings and even some mock ketchup (without all the sugar). They are all so easy to make with an immersion blender. Regular blenders or even wet spice grinders will do the job as well. This is a one jar recipe that stores in the same container its made in.
I'm not food scientist, but the vinegar and sherry concentrations allow this mustard to last in our fridge more than 3 months.
This recipe is really so simple.
Take all your ingredients and put them into a quart mason jar. Wide mouth is best, if not make sure your immersion blender will fit inside the opening. If not use any other container that allow your blender access.
Cover and let them sit overnight, up to 2 days. The majority of the liquid will be absorbed by the mustard seeds.
Whenever you have the time, insert your immersion blender and blend to the consistency you prefer. I like my mustard chunky as seen in the pictures.
Put your lid on the mason jar and stick it in the fridge... you are done. So easy. Do not eat the mustard right away however, it will be bitter for 24 - 48 hours. Not a scientist, but I assume breaking apart the whole mustard seeds releases some components that need time to oxidize and mellow once released.