What do you say about someone who does something as a hobby, but has higher knowledge than others and can transfer his/her hobby into a profession?
Example sentence: "Adam has superior knowledge about coffee. He's a ____"
I thought about Expert or Professional, but they feel too high on the spectrum.
connoisseur
a person who is especially competent to pass critical judgments in an art, particularly one of the fine arts, or in matters of taste:
a connoisseur of modern art.
a discerning judge of the best in any field:
a connoisseur of horses.
aficionado
an ardent devotee; fan, enthusiast.
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