A wok is then prepared for smoking the duck with black tea leaves. Theaflavins contribute to the bitterness and astringency of black tea. Traditionally, Darjeeling teas are classified as a type of black tea. Morocco consumes green tea with mint rather than black tea. Americans came out of the war drinking predominantly black tea. In Azerbaijan, savory is often incorporated as a flavoring in black tea. It is made from a strong brew of black tea blended with condensed milk. Saffron-rice plov is the flagship food in Azerbaijan and black tea is the national beverage. More flavors such as black tea and brown sugar have appeared. Since then the nation has become a major producer of black tea. Black tea is sometimes consumed with ginger. This grading system is based upon the size of processed and dried black tea leaves. Black tea is Azerbaijan's national drink. Iranians prefer to drink their hot black tea with sugar. The grading system is based upon the size of processed and dried black tea leaves.