Why classic punch is one of sour, two of sweet, three of strong, four of weak

Punch has a four-line rule: one of sour, two of sweet, three of strong, four of weak. It's a ratio, so it scales to any crowd.

Pick your guest count, glass size and ratio below and get the litres, limes and bottles for the bowl, plus its real strength. Learn why the "weak" part matters, why one big block of ice beats cubes, and how to make the same punch alcohol-free.