Nowadays there is a contemporary gallery in the Stables of Topkapı Palace about the culture of coffee in Istanbul. ( http://www.topkapisarayi.gov.tr/en/500-years-turkish-coffee-topkap%C4%B1-palace-museum )
Istanbul was actually the capital where coffee turned to be a transformative substance for the urban life. It was in 1550’s when the seeds had been first arriving through Alexandria from Ethiopia. Possibly, the beans were first brewed by the Yemenite Sufi people. All in all, there is a certainty about the fact that coffee as a product originates from the Red Sea.
And then, the first coffeehouse of the city (and the world) was opened in the old town close to the Topkapi Palace. According to the tax records, there were more than two-hundred around downtown. This process in a few decades was an irreversible change first for the city and then the rest of the world in the following centuries.
Here is a biref article about this topic: http://www.theguideistanbul.com/news/view/1943/topkapi-palace-500-years-of-turkish-coffee/