Mustard is made from the seeds of the yellow, white, brown or black mustard plant, which are ground and mixed with a liquid to form a spreadable paste. A range of different mustards exist, all of which combine different liquids with different blends of seed types to achieve their individual flavors. Mustard is commonly used as a condiment in sandwiches, or as a hot and tart addition to sauces, spreads and salad dressings.
A Rose by Any Other Name
Mustard flour is just another name for mustard powder or dry mustard, which is composed of ground mustard seeds. Different brands may contain varying ratios of each type of mustard seed, making some kinds hotter than others. To turn mustard flour into spreadable mustard, mix it with just enough liquid -- such as water, wine or vinegar -- to form a smooth paste and let it sit for about 10 minutes so it can develop its complex flavors. The correct ratio of mustard to liquid will depend on the brand of mustard flour you're using, but a good rule of thumb is to mix two parts mustard flour with one part liquid.