Cadbury's 'Giant Bar' of Dairy Milk chocolate, 1996.
© Science Museum / Science & Society Picture Library
Chocolate melts at quite low temperatures which allows it to be cast easily. If chocolate cools too quickly it could solidify before it fills the mould and the ingredients would separate out. To prevent this the mould is warmed to almost the same temperature as melted chocolate, filled, and vibrated. This gets rid of air bubbles and distributes the chocolate around the mould. Cadbury's introduced its milk chocolate into the British market in 1905, and by 1913 Cadbury's Dairy Milk was the company's best selling brand. Cadbury's slogan 'a glas and a half of full cream milk in every half pound' began in 1938, and their recipe for chocolate remained basically the same throughout their history.