Your grandmother was using a traditional approach that may have matched the corn available to her.
The best cooking advice is often this:
Pay attention to the food in front of you.
Not every recipe needs the same amount of time.
The Final Verdict
For typical fresh corn on the cob:
Boil for about 5–10 minutes.
For older, tougher corn:
Longer cooking may be needed.
For a family recipe passed down for generations:
Sometimes the tradition matters just as much as the technique.
So the debate is not really about who is right.
It is about understanding why both methods exist.
Your father-in-law is cooking for the corn we usually buy today.
Your grandmother was cooking the way generations before her learned.
And honestly, the perfect ear of corn is the one that tastes best to you.
