Coffee should be brought to a hard boil on a medium heat. Allow to percolate for seven minutes. After the seven minutes turn down burner to a low heat for an additional three minutes on a slow perk....
About 50.4 seconds is the estimated time ! I've heard that 50.5 works good too.
I'm not sure that the 50.4 to 50.5 range is sufficient to answer the question. I propose 45 to 59 seconds to account...