Brandy is made from early grapes in order to achieve higher acid concentration and lower sugar levels. Base wine generally contains smaller amount (up to 20 mg/l) of sulphur than regular wines, as it creates undesired copper(II) sulfate in reaction with copper in the pot stills. The yeast sediment produced during the fermentation may or may not be kept in the wine, depending on the brandy style. Brandy is distilled from the base wine in two phases. In the first, large part of water and solids is removed from the base, obtaining so-called "low wine", basically a concentrated wine with 28–30%
Brandy techniques. Since these are considered "protected designation of origin", a brandy made elsewhere may not be called Cognac in these jurisdictions, even if made in an identical manner. Brandy has a traditional age grading system, although its use is unregulated outside of Cognac and Armagnac. These indicators can usually be found on the label near the brand name: In the case of Brandy de Jerez, the Consejo Regulador de la Denominacion Brandy de Jerez classifies it according to: Russian brandies (traditionally called "Cognac" within the country), as well as brandies from many other post-Soviet states (except Armenia) use the traditional