A new classification of tequila added in the summer of 2006 this tequila must be aged for more than three years. Following the same rule as an ??Anejo??, distillers must age the spirit in barrels or containers with maximum capacity of 600 liters. With this extended amount of aging the tequila becomes much darker, more of a Mahogany color, and is so rich that it becomes difficult to distinguish it from quality-aged spirits. After the aging process, the alcohol content must be diluted by adding distilled water. This Extra Anejo is extremely smooth and complex and is reminiscent of the fine cognac.?