Stay clear of this establishment.
You would normally expect of a bar/restaurant to provide a pleasant service to paying customers, not rude, confrontational attitudes.
Sadly for Eier Carl, you wont get pleasant service. So do them a favour and pass them by and go find one of the many other options available steps away.
1) One of the servers was not willing to provide a glass of tap water after our entire group had ordered beers and ensued to argue that he wanted to charge for the tap-water and that one of our party was stupid for thinking a glass of tap water would be free.
2) Not being a fully fledged German speaker myself, I decided to go for the Alsterwasser, as pointed out in "their" English menu that this was their version of a "Radler"
Upon delivery of the drinks from possibly the female owner or boss? I declared "Radler" to her which seemed to confuse her and for unknown reasons trigger aggression.
One of our party who spoke German was able to decipher that the she said Radler is for dogs and to go drink it outside with them. We mentioned that it states in your menu that this was your version of Radler. Utterly bizarre mentality and reaction, we took our money elsewhere for drinks/food.
I suggest anybody reading this does too. read more