title_body: How do flavors like vanilla and hazelnut get into coffee
upvoted_answer: In a coffee shop (assuming both places like Starbucks or non-chain versions), flavour syrups are a staple. Some have their own range, others use generic manufacturer's that are also used in other cooking or bartending applications.
  
  I'd assume a dash or two of these are added to your coffee and voilá: Vanilla (hazelnut/caramel/...) coffee.
  
  Another option are flavoured coffee beans, but for a coffee shop, that's pretty unlikely, as they would have to keep various beans at hand and switch between orders.