The key lies in a contradiction regarding when they first knew about the crime.

Nutmeg accuses Ginger of running away with The Java Joltinator 3000, and even says that Ginger nearly knocked him over, this suggests prior knowledge of the theft.

This is inconsistent with Nutmeg’s claim that the first time he knew about the crime was when the police barged in.

And so it appears the bitter truth points to Nutmeg as the espresso machine thief!