Malt vinegar is made by malting barley, causing the starch in the grain to turn to sugar. An ale is then brewed from the sugar and allowed to turn into vinegar, which is then aged. A cheaper alternative, called "non-brewed condiment," is a solution of 4-8% acetic acid colored with caramel. Malt has a distinctive flavor that contributes to the flavor of malt vinegar and brewed beverages such as beer. Malt vinegar is popular for pickling, especially walnut pickles. It is most famous as the companion to fish and chips. Any English recipe calling for vinegar typically uses malt vinegar unless otherwise noted.
Malt vinegar contains gluten, and is not recommended for gluten-free diets. One possible substitution is Cider Vinegar.