Coffee milk is a drink made by mixing coffee extract, sugar and milk together. Coffee milk are sold either in bottle or paper carton. Although there are coffee with milk sold in cans but these products contain less milk than coffee milk. Therefore coffee milk is a milk with a sweeten coffee flavor. Then, coffee milk is sold by milk companies, not by coffee companies.
Coffee milk was invented in 1923 by a milk company, Moriyama milk industry. It was first sold at Kozu station of Tokaido main line and gradually expanded to other stations. However, coffee milk is much popular at hott springs and public baths, where sold either in fridges or in vending machines.
Coffee milk together with milk in bottles were sold with paper caps, which were sometimes difficult to open. Nowadays paper caps are replaced by plastic lids which are more easy to open.