Where your index finger and thumb meet, in the web of your hand; you can pinch closest to the outside. There you will find about the same resistance as rare meat. Move a little further in, about half the distance to the connection joint and you will have about the same resistance as medium meat. And just below the joint you will find the resistance of about well done meat. This is right about where you find that pressure point, so if you pinch hard enough you'll know.

Wouldn't this be totally dependent on the temperature of the grill and starting temp of the meat? Just use a thermometer! Thermometer solves many problems. Thermometer loves me and I love thermometer.

Isn’t this for whole muscle meat not mince?

Yes but i find it still works relatively well for ground. It's more a guideline more than actual rule, even for muscle. You can always stab-cut with your spatula in the middle to check color.

Back when I was cooking professionally, in some states (the one I was in) you could not serve medium burger unless you ground in-house. That way the restaurant could control the cleanliness and amount of possible contamination in the ground. Since then I have refused to serve anything but medium well from store bought ground.

You can always stab-cut with your spatula in the middle to check color.

My chef would have fired me on the spot for doing this.

People just like to be lazy and not use a thermometer. Or if theyre like my dad, they dont need no goddamn toy to tell them how to do it right.

Depends where you're working, a greasy spoon no one would care just serve stab down, 2-3* + no way. Home cooked, do what needs done. Obviously you said chef so I'm assuming and so would the customer a higher graded restaurant, quality and presentation is expected. You should probably know your meat and temps before you put an apron on.

"Without my thermometer I am nothing. Without me my thermometer is still pretty useful"