We hate to be the ones to tell you this, but the white stuff oozing out of your salmon is your fault. It happens to everyone, and it looks gross. The good news is that it doesn't have to be that way and we're going to tell you how to fix it.
First, let's get to the bottom of what that stuff is. The totally harmless, but wholly unappetizing white gunk that seeps out of salmon filets as they cook is just coagulated protein -- also known as albumin. (To clarify, the correct spelling is albumin with an "i." You may have also heard of albumen, with an "e," but albumen is the term for egg whites. They're two different things.) This sounds bad, but it's absolutely safe. Albumin gets pushed out of the muscle fibers of fish as it cooks, coagulating at the surface. This will happen to all salmon, no matter what you do. It has been hypothesized that the way you cook salmon -- how fast and how long -- causes albumin, but this is not true.
America's Test Kitchen tested the cooking theory AND talked to Donald Kramer -- a professor of seafood science at the University of Alaska -- and concluded that the way you cook fish will not stop albumin from collecting at the surface. While they did see some more albumin with salmon that was purposefully overcooked, it collected on all the salmon to some degree. But don't despair, they did find a way to significantly minimize the collection of albumin: a quick brine.
Just 10 minutes in a basic brine solution (about 1 tablespoon of salt per cup of water) before cooking results in less white stuff. According to America's Test Kitchen, this is because "the salt partially dissolves the muscle fibers near the surface of the flesh, so that when cooked they congeal without contracting and squeezing out albumin."