This is a classic example of a restaurant where good food and good location are not enough to ensure good business:
1. The booking system is a mess: even though it is stated in the Groupon voucher that we may either phone or WhatsApp to book (and we did phone twice and left messages for our booking), the service staff simply admitted that they did not retrieve phone messages, and would only accept bookings via WhatsApp; they refused to give us a table until we agreed to leave before 8:30pm (we arrived at 6:45pm for our 7pm "booking").
2. We bought a Groupon voucher for a dinner set for 6 persons, expecting that the food portion for each course would be enough for 6 persons:
Set dinner for 6 people (as detailed in the Groupon offer)
•Italian mixed green salad
•Fass platter
•Clams in white wine sauce
•Roasted German pork knuckle with sauerkraut
•Grilled 12oz US prime beef rib eye steak with sweet potato fries
•Fass combo platter
•Spaghetti carbonara
•Whole cake
•6x Bitburger draught beer / soft drinks
There were total 11 clams in the "clam in white wine sauce", the "12-oz rib-eye steak" was at most 8 oz, and the spaghetti carbonara was enough for 2 persons only. The food quantities for the other courses were adequate for 6 persons, so we wonder why some courses were "under-provided".
3. To be fair, the retaurant location is very convenient, food quality is good, and beer is excellent, and it is unfortunate that the way the service staff handled (telephone) bookings destroyed further business for the restaurant.