Why Does Salt Have an Expiration Date?
Salt is an incredibly common ingredient that most of us take for granted. It is a simple inorganic (which means “non-carbon-based”) molecule made up of two tiny ions, sodium and chloride, but its ability to flavor and retain is what makes it valuable – so valuable that it is reflected in the word “salary”. “
Salt retains food by wicking moisture away, inhibiting the growth of harmful bacteria and stimulating the growth of beneficial bacteria – so why do canisters of this ingredient have a shelf life?
It’s not the sodium chloride that’s to blame, but the additives that some manufacturers mix with it to prevent clumping or the addition of nutrients. Iodine, anti-caking agents, and trace minerals in pink, red, or black salts may degrade over time, but decomposition does not guarantee harm. Supplements may also not do the job – your salt may start clumping and you won’t be able to count on it as a reliable source of iodine – but less effective iodine won’t harm you, and you shouldn’t do it anyway. I don’t see mold in the salt shaker.
However, this does not mean that you should neglect salt – even salt without additives – or store it the old way. The hygroscopic (water-absorbing) properties of salt make it a poor candidate for outdoor exposure. It not only absorbs moisture from the air, but it also smells in the kitchen, which leaves behind lumpy, smelly salt.
Store salt in an airtight container in a cool, dark place. If, like me, you store salt in a salted pig or other container by the stove, resist the urge to keep it full at all times and monitor it to make sure it is not contaminated with food pieces, splashes of water or oil, or other kitchen gizmos.
And like everything else in the kitchen, throw in the salt if you see any bugs or mold. While none of them do well on pure salt, kitchens are messy places, and even the purest sodium chloride isn’t good for old, rotting food or outright spills.