I make ketchup a lot. I've never made mustard.
(In recipes that call for whey, I usually substitute dill pickle juice from real pickles like Bubbies. The point is the bacteria that drive fermentation, so juice from the kind of pickles that are found at room temperature in the store won't work.)
From Nourishing Traditions:
MUSTARD
Makes 2 cups
1½ cup (12 ounces) ground mustard
½ cup filtered water
2 tablespoons whey
2 teaspoons sea salt
juice of 1 lemon
2 cloves garlic, mashed (optional)
1 tablespoon honey (optional)
2 tablespoons whole mustard seeds (optional)
Mix all ingredients together until well blended, adding more water if necessary to obtain desired consistency. Place in a pint-sized jar or two 8-ounce jars. The top of the mustard should be at least 1 inch below the top of the jar. Cover tightly and keep at room temperature for about 3 days before transferring to cold storage.
Use of mustard seed dates back to antiquity, both for its epicurean and medicinal properties. A member of the brassica family, related to broccoli and cabbage, mustard is valued for its seed, which contains a compound called sinigrin. During grinding, enzymatic action liberates the pungent principle from the sugar molecule to which it is attached. Sulphur compounds and oils are also released. These compounds have a penetrating odor and an irritating effect on the skin and mucous membranes. Paradoxically, mustard compounds have been used throughout the world for the treatment of diseases of the lungs and sinuses. During the Tang Dynasty in China, mustard was used as a treatment for pulmonary diseases. The Egyptians recommended mustard in respiratory therapy, and in the Middle Ages mustard was used against asthma, coughs and chest congestion. The English physician Herberden also recommended mustard seed to treat asthma.
I'd love it if you posted your ketchup recipe. I just bought a home fermentation kit to make pickled stuff that way instead of the vinegar/salt/canning method.
