Armagnac is traditionally distilled once, resulting in 52% of alcohol. This results in a more fragrant and flavorful spirit than Cognac, where double distillation takes place. Long aging in oak barrels softens the taste and causes the development of more complex flavours and a brown colour. Aging in the barrel removes a part of the alcohol and water by evaporation (known as part des anges—"angels' tribute" or "angels' share") and allows more complex aromatic compounds to appear by oxidation, which further modifies the flavour. Since alcohol evaporates faster than water, the alcohol degree is naturally reduced by an average of 0.4% per year depending on the characteristics of the cellars (average temperature and humidity). When the Armagnac is considered as matured, it is transferred to large glass bottles (called "Dame Jeanne") for storage. The main difference between Armagnac and other spirits is, that due to its relatively low proof, it is generally not diluted with water.
Armagnac is sold under several classifications, mostly referring to the age of the constituent brandies. Armagnac is allowed to be sold under vintages. When Armagnacs of different ages have been blended, the age on the bottle refers to the youngest component. A three-star, or VS, Armagnac is a mix of several Armagnacs that have seen at least two years of aging in wood. For VSOP, the aging is at least three years, and for XO, at least six. Hors d'age means the youngest component in the blend is at least ten years old. Older and better Armagnacs are often sold as vintages, with the bottles containing Armagnac from a single year, the year being noted on the bottle.