from bourbon, U.S. regulations defining bourbon neither require nor prohibit its use. Bourbon also was and is made in other U.S. states. The largest bourbon distiller outside of Kentucky and Tennessee is MGP of Indiana, which primarily wholesales its spirits products to bottling companies that sell them under about 50 different brand names – in some cases, misleadingly marketed as "craft" whiskey, despite being produced at a large wholesaler's factory. Production process To be legally sold as bourbon, the whiskey's mash bill requires a minimum of 51% corn, with the remainder being any cereal grain. A proposed change to U.S. regulations will expand allowable "grains" to include seeds of the pseudocereals amaranth, buckwheat, and quinoa. A mash bill that contains wheat instead of rye produces what is known as a wheated bourbon. The grain is ground and mixed with water. Usually mash from a previous distillation is added to ensure consistency across batches, creating a sour mash. Finally, yeast is added, and the mash is fermented. It is distilled to (typically) between 65% and 80% alcohol using either a traditional alembic (or pot still) or the much less expensive continuous still. Most modern bourbons are initially run off using a column still and then redistilled in a "doubler" (alternatively known as a "thumper" or "retort") that is basically a pot still. The resulting clear spirit, called "white dog", is placed in charred new oak containers for aging. In practice, these containers are generally barrels made from American white oak. The spirit gains its color and much of its flavor from the caramelized sugars and vanillins in the charred wood. Straight bourbon must be aged at least two years, and blended bourbon must contain at least 51% straight bourbon on a proof gallon basis (i.e., most of the alcohol in the blend must be from straight bourbon). The remainder of the spirits in a blended bourbon may be neutral grain spirits that are not aged at all. If a product is labeled merely as bourbon whiskey rather than straight or blended, no specific minimum aging period is prescribed – only that the product has been "stored at not more than 62.5% alcohol by volume (125 proof) in charred new oak containers". Bourbons gain more color and flavor the longer they age in wood. Changes to the spirit also occur due to evaporation and chemical processes such as oxidation. Lower-priced bourbons tend