Cognac is a specific type of brandy. It is produced/distilled from white wine (grapes) from the region. It is located about 1.5 hours east of Bordeaux in France. Legally it must be distilled twice, using only cooper pot stills. It also legally needs to be aged in French oak barrels for a minimum of two years.
A big thing to remember is that cognac can only be distilled from October 1- March 31 st . Anytime outside of these 5 months and it will just be labeled brandy. Why? Wine made with sulfites can’t be used for cognac. As the weather gets warmer post winter/spring, newly produced wines would need sulfites to hold up.