Cold stabilization is a way of clarifying wine to remove unwanted tartrate crystals and ensure that the wine is properly stabilized (hence the name). It's a common procedure for many white wines and a relatively simple process: The wine is chilled almost to its freezing point, which causes the tartrates to precipitate out of the wine. The remaining wine is then racked off. By the way, those crystals you occasionally see on the cork show that the wine wasn't cold-stabilized, since cold stabilization eliminates the tartrates that appear as crystals. See also centrifuge, filtering, fining, racking, and clarify.