Why can't Turkish coffee be poured out?

The reason why Turkish coffee can't be poured out is because the heating produces foam and the foam expands, so it seems that it can't be poured out

Before the Turkish coffee was about to boil, a layer of golden foam appeared on the surface, which gradually increased and poured in quickly. Immediately remove the pot from the fire, take out the foam with a spoon and put it in the cup, then put it on the tempering. After several times of boiling, the coffee gradually thickens, but it is not finished until it is boiled to half its original size.

The history of Turkish coffee: Turkish coffee is a kind of coffee with original cooking method, which is thick and fragrant. Turkey, Greece and Balkan countries, which were ruled by the Ottoman Turkish Empire in history, are still drinking Turkish coffee.

There is a proverb in Turkey: "Have a cup of Turkish coffee and remember your 40-year friendship." Coffee shops with signboards can be seen everywhere on the streets of Turkey. Many Turks, especially women, also like to use the residue traces left by drinking Turkish coffee for divination, which adds a bit of mystery to Turkish coffee.

On the streets of Turkey, the heat source of Turkish coffee is not mainly gas, but a large basin of magical heating sand. Put the sand in a wok with a direct fire and heat it until it boils. When the Turkish pot is wrapped in sand, the sand will transfer heat to the Turkish pot. This heating method is better than uniformity. If you have a chance to go to Turkey, please don't waste the opportunity to watch this wonderful excerpt.

The above contents refer to Baidu Encyclopedia-Turkish Coffee.