I once saw Bobby Flay flipping out because Guy Fierri kept flipping some shrimp on a grill. What did those shrimp ever do to you? he said. Well, does Flay believe the same thing about steaks and burgers? That you should only flip them once? Probably. Does he have a good reason? Not really. This cooking myth is based on the same kind of thinking that many hard and fast ‘rules’ are based on: magical thinking.
The reason usually given for only flipping a steak or burger once is that if you flip them too much it will ruin the sear and thus the flavor. The question to ask is why? Why is this so? Is there a such thing as searus interruptus? If you turn over a steak too soon, thus interrupting the searing process, will the sear then fail to fully develop when you flip it back?
Of course not. If you have your heat nice and high, whether a pan or a grill, you can flip a steak as many times as you want with no danger of not developing a good sear. Yes, you may want to leave your steak or burger alone for the first few minutes before flipping it, but this has more to do with having it release from the pan than allowing a sear to develop. During this time, it’s best not to move it at all. This is less of a problem with the outdoor grill, however.
The truth is that frequent flipping will not hinder a good result, it will ensure it. Flipping often is almost like cooking both sides at once, thus ensuring that the steak cooks evenly. If you only flip once, you are cooking only from one side and risk having a thicker and harder sear on one side while developing a dry and over-cooked interior.
You can flip a steak or a burger once every 30 seconds or so if you want. This will not only allow a sear to develop (as long as your cooking surface is hot enough) but it will also ensure even, and quicker cooking while helping you to get just the right degree of doneness.
To sum it up, the dogmatic rule that you should only flip a steak, burger (or any other seared meat) once is a myth. It is based on nothing but vague supposition and magical thinking. It is actually better to flip often to make sure you get even cooking.