The Big Bang Theory - Season 9, Episode 22
  • Episode Title: The Fermentation Bifurcation
  • Episode Run Time: 30
  • Episode Air Date: 2016-04-28 20:00
  • Episode Summary: The gang goes to a wine bar and runs into Penny's old boyfriend, Zack. Also, Bernadette gets stuck spending the evening with Sheldon when she can't go wine tasting with the group, and things don't go as planned when Koothrappali introduces his new girlfriend, Claire.