Why does my sea salt have a best by date? [duplicate]








**This question already has an answer here**:
 
 




[Do chemicals have an expiry date?](/questions/20039/do-chemicals-have-an-expiry-date)

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Closed last year.



Seems like it should be good for thousands of years, if not millions.




This table (no pun intended) from Morton Salt explains why table salt has a shelf life:


[MORTON SALT EXPIRATION GUIDE](https://www.mortonsalt.com/article/morton-salt-expiration-guide/)


Essentially, salt is hygroscopic, which means it absorbs water from the air. Thus, unless it is stored under very dry conditions, the salt granules will clump together over time.


This clumping is inhibited by anticaking agents. According to Morton, in the presence of an anticaking agent, table salt has a shelf life of ~5 years. I.e., under typical storage conditions, it should last that long before it begins to clump. Without an anticaking agent, it's ~3 years.


Interestingly, even if caking weren't an issue, if the salt is iodized, and you want it to remain iodized, it still has a shelf life of ~5 years. That's because, as the table explains, "iodine can dissipate over time."


Finally, as suggested by Karsten's comment, the cardboard container will also break down over time.


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Salt does not expire. It does not decompose under normal conditions, and as you correctly assume, it could sit around for millions of years without undergoing any change. Sitting around for millions of years is actually exactly what it does as rock salt. However, while salt does not expire, other constituents of your salt package probably do; the expiration date is actually of the container itself.


Sea salt is different than table salt. It is less processed and does not have anticaking agents nor iodine compounds added to it. Also, while sodium chloride is hygroscopic, it is not that hygroscopic. It is rarely, if ever, used as a desiccating agent. Sea salt crystals tend to be larger and rougher than table salt particles and do not clump up as easily due to moisture. Therefore, iodine dissipation and bulking of salt particles are not as much of a concern as the other answer claims while ignoring that you explicitly specified "sea salt" instead of "table salt".


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