Here is the full list of all 17 Tavern Master achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
Finish all of the researches
Reach the last reward from quests
Have a successful adventure which had less than 30% chance to succeed
Have all food on 5 stars
Unlock the fourth floor
Do an event for the king and the queen
Have all 6 historical paintings
Have 30 employees
Have 100.000 coins at once
Unlock the third floor
Have one food dish on 5 stars
Have a 5 star hotel room
Build a hotel room
Unlock the second floor
Level up an employee to level 10
Unlock the kitchen
Have a bar with all barrels purchased and filled