MartinF DiggingDogFarm
TVWBB Fan
Kenji over at the Serious Eats Food Lab has written about this. He has pictures that show the difference in texture of the meat, depending in when it is salted. http://aht.seriouseats.com/archives/2009/12/the-burger-lab-salting-ground-beef.html
Salted just before cooking = loose, tender meat
Salted before making patties = sausage-like texture
I've posted this before, but it seems the topic is like politics or religion to some folks. They will insist on mixing in the salt before making patties, and they mightily resist any suggestion that their approach may have any flaw. They'll even attack the photos as some sort of trickery. Very strange.
I read that when it was first published.
Ultimate results are all in the technique, in my experience, pre-salting is not a problem if you salt lightly, don't over mix and cook immediately.
I've cooked burgers for over 35 years and I've never had one look anything like the second burger!
~Martin