While pasteurizing caviar will maintain its newly-packed caviar freshness for up to three months, all gourmet caviar is perishable and should be treated gently. Caviar should be stored between 26 and 32 degrees Fahrenheit. This can be done either by putting the tin in the coldest part of the refrigerator or by placing the tin in a bowl and surrounding it with crushed ice. Unopened fresh caviar will last up to a few weeks, but once the tin in opened, it should be eaten right away. If caviar is left in the tin, the surface should be smoothed and a sheet of plastic wrap should be pressed directly onto the surface before placing it back in the refrigerator. Turn the tin over each day so the oil reaches all of the eggs.