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 of brandy produced. Cognac and South African brandy are examples of brandy produced in batches while many American brandies use fractional distillation in column stills. After distillation, the unaged brandy is placed into oak barrels to mature. Usually, brandies with a natural golden or brown colour are aged in oak casks (single-barrel aging). Some brandies, particularly those from Spain, are aged using the solera system, where the producer changes the barrel each year. After a period of aging, which depends on the style, class and legal requirements, the mature brandy is mixed with distilled water to reduce alcohol concentration and