Nothing defines a culture like what it eats and drinks. Romulan Ale for example comes to mind. I don't know how many cons I've been to where someone in a startrek "T shirt/uniform," has offered me a strange blue liquid of suspicious origins. With that in mind, I challenge YOU the reader to come up with some new drink/food/taste and put it down here in the comments.
For example: On the planet Klum, the natives there use the most unique spice. It is called Haliq and it comes from a bush like plant that grows in the long low plains of the northern continent. Harvested from the buds of that bush, Haliq appears as a greyish powder with a light almost oaky smell. Ingestion of Haliq causes a minor rewiring of sensory input. Colors actually have a taste. For example, if you are looking at yellow the dish will have a more sour taste, whereas red adds sweetness. Cooking with Haliq requires balance and a good design sense!
Now it's your turn!!