Noun without article refers to a concept, a type. Kan du lide kaffe? (Do you like coffee?) is a question about coffee in general, not about the coffee in the cup in front of you. Jeg vil gerne have en kaffe og to te, tak! (One coffee and to teas, please!) refers to concrete objects of a certain size an quality: One of those that you make.
Choose general (without article: en/et/nogle/noget) form or concrete form in the drop down list.