This article does not have any sources. (August 2014)
Mustard is prepared by grinding the seeds of the Mustard plant, and mixing them with water or vinegar. Depending on which seeds are taken, and/or how much vinegar is added, the mustard may turn out hotter or less hot.
Most mustard is made available as a bottled condiment and can be spread on a slice of sandwich bread or squirted onto a hotdog along with ketchup, horseradish and other spices. It is also commonly found in most fast-food restaurants in the form of a small packet which the diner may open and squeeze into the dish of choice, but it is usually already included in the average hamburger bun.