The mash for Jack Daniel's is made from corn, rye, and malted barley, and is distilled in copper stills. It is then filtered through stacks of sugar maple charcoal. The company refers to this filtering step as "mellowing". This extra step, known as the Lincoln County Process, removes impurities and the taste of corn. The company argues this extra step makes the product different from bourbon. However, Tennessee whiskey is required to be "a straight Bourbon Whiskey" under terms of the North American Free Trade Agreement and Canadian law. A distinctive aspect of the filtering process is that the Jack Daniel's brand grinds its charcoal before using it for filtering. After the filtering, the whiskey is stored in newly handcrafted oak barrels, which give the whiskey its color and most of its flavor.