Is coffee a common noun

Yes, the Word coffee is a common noun, a Word for any coffee of any kind.

A proper noun is the name of a specific person, place, thing, or a title; for example:

• Professor John C. Coffee, Columbia University Law School, New York, NY
• Coffee County, Tennessee
• Coffee Street, Houston, TX or Coffee Street, Medway, MA
• Maxwell House Coffee
• "Chinese Coffee", 2000 movie with Al Pacino and Jerry Orbach