How Long Can I Keep Caviar in the Refrigerator?
First off, most caviar should never be frozen, as the freezing/thawing out process usually damages the shell of the roe. This leads to a "mushy" texture and compromised taste.
For most types of caviar, including all Russian and Iranian types, and American types (California White Sturgeon, Siberian Sturgeon, Paddlefish, Smoked Trout, Alaskan Salmon), the caviar can remain fresh for up to 4 weeks if properly refrigerated. However, the 4 week shelf life is highly dependent on how well the caviar is maintained.
Once the caviar tin is opened, the remaining caviar should be consumed within 3 to 4 days. The shelf life is drastically reduced once opened because of the contact with air, and the fact that the caviar is now stored in the original tin with air inside (where the now consumed caviar used to be).
Lastly, make sure that nothing is placed atop the caviar tin. Any substantial weight atop a tin will press upon the caviar roe inside and ultimately cause them to burst.
Conclusion: Up to 4 weeks (if properly stored) for unopened tins. Between 3-4 days for partially consumed opened tins.