An unopened tin of caviar and one that has already been opened are not in the same condition. The first remains sealed as its packer intended; the second has been exposed to air, utensils and hands. That is why the reference for storing either one is not a number repeated online, but the label on the actual tin in front of you.
Before opening: follow the physical label
When the caviar arrives, check that the container is intact and find the date and storage temperature. Refrigerate it exactly as directed. The most convenient part of the fridge may not be the right one: avoid repeated temperature changes at the door and check that the chosen place meets your tin's instructions. Do not freeze it on your own initiative to extend a date.
A use-by date and a best-before date mean different things. AESAN explains that foods past their use-by date are not considered safe. If the tin arrives damaged, its information is illegible, or you have doubts about refrigeration during delivery, do not try to settle them by tasting the caviar. Ask the seller before serving it.
Set the table while the tin is still closed
Have the plates, spoons, ice support if you intend to use one, and any accompaniments ready. The caviar can then remain refrigerated until close to serving. For a longer tasting, rest the cold tin over ice in a suitable container, keeping melted water out of the product. Ice is not a reason to leave the tin forgotten on the table.
After opening: look for the new instruction
Opening the package can change both the time limit and storage conditions. AESAN notes that the manufacturer determines a secondary shelf life and, where needed, new instructions for opened food. Find that specific guidance on your label; if you cannot, ask the product supplier. Do not apply the timeframe of another brand or another type of caviar to your tin.
Serve with clean utensils, and do not return a spoonful that has touched other foods to the container. Close and refrigerate anything remaining in accordance with the manufacturer's physical instructions. If you know some guests will eat later, consider two smaller tins beforehand: opening only what you are about to serve avoids unnecessary handling.
The rule worth remembering
The useful rule is not ‘it lasts so many days’, because that depends on the product and its instructions. It is a sequence: read the label on arrival, maintain the specified cold conditions, open close to serving, then check the directions for the opened tin. If an article conflicts with the package, the physical package takes precedence.
