Coffee upside down: why Indonesians at first overturn a glass, and then drink

It was so moved long since. If you sometime get to the Indonesian Special Region of Aceh, surely taste Kupi Khop coffee. It is one of local sights. Still it call "the turned coffee". Counter that make drink in a special glass which then overturn upside down and drink from a straw. Under a glass there is a saucer that coffee did not spill. It not trick, and ancient tradition. Such way of giving was thought up by fishermen several centuries ago. They were warmed by hot coffee, but on air it quickly cooled down. Thermoses then yet were not, besides in a cup flew...