Questions & Answers about Wir brauchen den süßen Senf für die Wurst.
How would I modify this sentence to specify the sausage is from Munich, using the geographic adjectives taught in this lesson?
You would say für die Münchner Wurst. When you form an adjective from a city name by adding -er (like Münchner, Berliner, or Wiener), the word becomes indeclinable. This means it never takes grammatical endings, whereas a normal adjective would take an -e ending here for the feminine accusative case.
Why does the adjective have an -en ending in den süßen Senf?
Senf is a masculine noun (der Senf) and is the direct object of the verb brauchen, putting it in the accusative case (den). Because the definite article den already clearly signals the case and gender, the adjective takes the weak declension ending, which is -en.
Could I leave out the definite articles and just say Wir brauchen süßen Senf für Wurst?
Grammatically, yes. Dropping the articles changes the meaning from "We need the sweet mustard for the sausage" (referring to specific items you are preparing to eat) to a general statement: "We need sweet mustard for sausage." Notice that if you drop the article den, the adjective must take over the job of showing the masculine accusative case via the strong declension, which is why it remains süßen Senf.
Is süßer Senf a specific cultural thing in Germany?