
...and I could smell German chocolate cake,
which is my favorite.
The Big Bang Theory Season 1, Episode 16

Quartz, from the
German "quarz"
The Big Bang Theory Season 12, Episode 2

meaning German.
The Big Bang Theory Season 12, Episode 7

(SINGING IN GERMAN)
The Big Bang Theory Season 10, Episode 20

and my bowel movements run
like a German train schedule.
The Big Bang Theory Season 5, Episode 10