The Big Bang Theory Season 9 Episode 22
The Fermentation Bifurcation
Penny announces to all of her freidns that she won tickets to a wine tasting from her job, and invites everyone to go.
Sheldon has no interest in drinking again, and Bernadette is pregnant, so neither of them can go. Everyone else decides to, and Sheldon invites Bernadette to spend time with him while the rest of the group are out.
Bernadette agrees, but she's hesitant to spend a Saturday night with Sheldon.
At the wine tasting, they run into Penny's ex-boyfriend.
He asks the guys about "science" and they tell him a little about their invention. Zack asks if they would use it for the military, which has Leonard and Howard second-guessing whether they should keep moving forward with the project. Leonard especially feels nervous about it, and doesn't want his invention to be used as a weapon.
Raj also invites Claire to the tasting, and asks everyone not tell about the fact that he's also seeing Emily. They do a good job of avoiding the subject, but Raj ends up implicating himself anyway.
Bernadette ends up having a great time with Sheldon because he doesn't focus on her pregnancy, and they play a fun game of Dungeons and dragons. They also sample different kinds of toast.