Where did the phrase piping hot come from?
Answers:
I believe that this comes from when buildings were heated with steam. Their were pipes that would take steam from the boiler and transport it to the radiators that were in each room. You had to be careful not to touch the pipes (or the radiators) because they were "Piping hot".
This idiom alludes to something so hot that it makes a piping or hissing sound. [Late 1300s]
FROM THE PIPE??
The answers post by the user, for information only, UKQnA.com does not guarantee the right.