Here's how it evolved:
* Cork: Wine bottles were traditionally sealed with corks, and a good cork was essential for preserving the wine.
* Corker: This term, used in the 19th century, described a particularly well-made cork, one that would keep the wine fresh and flavorful.
* Corker (wine): By extension, "corker" started being used to refer to a bottle of wine with an exceptionally good cork, indicating a high-quality and well-preserved wine.
* Corker (anything good): The meaning then expanded further, becoming a general term for anything excellent, exceptional, or outstanding.
Therefore, "going to be a corker" means something is expected to be great or highly successful. The phrase has been used since at least the early 20th century, and its popularity continues today.