It happens to the best of us. You pick up a salt shaker at dinner only to find that nothing comes out – the salt is caked together in the bottom of the container!
If your day has been filled with other bad luck, you might vent your frustrations by exclaiming “When it rains, it pours!”
But would you believe… this saying (or at least this version of it) actually originates from salt! It was created by ad execs at the Morton® Salt Company in the early 1900s to sell the seasoning.
In 1911, The Morton® Salt Company began adding magnesium carbonate (an anti-caking agent) to salt which allowed it to pour freely, even in humid weather. (Today, the company uses calcium silicate.) To promote its new free-flowing table salt, the company took inspiration from the old 18th century proverb “It never rains but it pours.” The saying — which means when one bad thing happens, it tends to be followed by other misfortunes that make an already bad situation worse – wasn’t just one that most folks had heard time and time again, it also allowed for a clever play on words (the “it” in the proverb would be their salt, which does pour in rain.) After a bit of tweaking, the now famous “When it rains it pours” was settled upon and advertised.
Today, we use their slogan more than the original 18th century version of the expression!
Why Doesn’t Salt Pour Easily in Damp Weather?
Why does salt cake together on muggy or rainy days in the first place?
For the answer, we again look to weather lore.
When windows won’t open and salt clogs the shaker,
The weather will favor the umbrella maker!
This weather folklore tells us that wood and salt are both hygroscopic – a fancy word that means each likes to absorb moisture from the air. As wood soaks up moisture it swells and warps from its straight shape, which can make doors and windows harder to open. Similarly, when salt takes on moisture, its individual grains stick together and become too big to fit through the tiny holes in the shaker. This is why you sometimes see grains of dried rice inside salt shakers — the rice absorbs the moisture, freeing up the crystals.
From this, you can assume that whenever salt clumps (or wood swells), it’s a sign there’s a good amount of humidity in the air. And as you know, high humidity points to an increased chance of rain.
Tiffany Means is a freelance writer and a degreed meteorologist. She specializes in weather forecasting and enjoys making the subject of weather (and the science behind it) more relatable. She currently resides in the Blue Ridge Mountains of North Carolina.