There is no one answer to the question of what makes an altar wine unique. It could be the type of grape used, the aging process, or even the location where it is made. Whatever the case may be, altar wines are usually expensive and coveted.

Alto wine is made from grapes that are typically higher in acidity and tannins, which gives the wine a dry, chalky taste. This style of wine was once solely produced in regions such as Bordeaux, Chile and Italy, but it's now becoming more popular to find altars wine produced in the United States, such as in the Napa Valley.