I recently was at a bbq where the wife of the gentleman who stood up to cook at the hosts grill argued with me very matter-of-factly that it's necessary to rest a chunk of meat for 20+ minutes before slicing and serving. I said 5 minutes is sufficient and 20 minutes would result in a cold, greasy piece of meat but she argued on. I didn't even get to talk about the carry-over factor, juice redistribution or anything else. As soon as I reminded her that my father was a butcher and steak connoisseur, I lost her attention all together.
So, please put it to rest....
What is an acceptable length of time to rest a piece of meat at room temperature?
(What was cooked was a 1.25" slab sirloin steak on a very hot grill.)