Question

Some empty space is left in sealed wine bottles. Why

Answer 1

Answer: It increases the strength of the bottle, allowing it to hold the high pressure of sparkling wine/champagne. ... The empty bottle would be thrust bottom-end down onto this pin, puncturing a hole in the top of the punt, guaranteeing the bottle could not be refilled [folklore].

Explanation:

Answer 2

Answer:

increases the strength of the bottle, allowing it to hold the high pressure of sparkling wine/champagne. ... The empty bottle would be thrust bottom-end down onto this pin, puncturing a hole in the top of the punt, guaranteeing the bottle could not be refilled [folklore].