What is the fine-grained topic of the following text: I am hopeful that Portuguese wines will take off in the United States one day and I eagerly await the meteoric rise of Portugal’s great-value reds, either from a famed region like the Douro Valley or from lesser-known regions such as the Alentejo or Dão or Setúbal. Only return the topic.
The popularity and potential rise of Portuguese wines in the United States.