Chocolate whether emulsifying agents are added. Different manufacturers develop their own "signature" blends based on the above formulas, but varying proportions of the different constituents are used. The finest, plain dark chocolate couvertures contain at least 70% cocoa (both solids and butter), whereas milk chocolate usually contains up to 50%. High-quality white chocolate couvertures contain only about 35% cocoa butter. Producers of high-quality, small-batch chocolate argue that mass production produces bad-quality chocolate. Some mass-produced chocolate contains much less cocoa (as low as 7% in many cases), and fats other than cocoa butter. Vegetable oils and artificial vanilla flavor are often used
Aero (chocolate) Strawberry flavour and a new variation of a Caramel Aero. While bars were (and still are) produced with chocolate and a liquid caramel, the new Caramel Bubble Bar consists of a Caramel flavoured white chocolate centre with a milk chocolate coating. Japan has produced a number of unique Aero flavours, among them Vanilla Milkshake, Hot Milk, Green Tea and others. They usually consist of a flavoured, coloured chocolate centre and outer milk chocolate layer. Aero Cocoa (plain, Green Tea and Strawberry flavours) is also sold in Japan. Released in 2006, the Aero Vanilla Yogourt flavour was released only in Canada.