Here’s Why You’ll Find Rice Inside Salt Shakers in Some Restaurants- Food Science Experts Explain

When droplets of mist hang in the air, both rice and salt act as natural moisture absorbers. However, the two display a subtle difference. When salt crystals, which are essentially sodium chloride, absorb water, the water breaks down the chemical compound and pulls the sodium ions apart from the chloride ions. Once the two elements are separated, the salt dissolves in water, disappearing from the scene. On the flip side, when rice grains absorb water, they can hold the water for a long time, which often leads to drying up of the rice container. This fascinating contrast between salt and rice has inspired many restaurant professionals and even homemakers to add rice grains to their salt shakers. Speaking to Southern Living magazine, food scientist, Bryan Quoc Le, explains the science behind this trick.

Le shares that salt is an ionic compound that easily attracts water. In areas where humidity is usually high, like in Florida or Southern regions, the salt tends to quickly absorb the moisture in the air and dissolve at the edges. “As the salt recrystallizes from changes in the environment, the salt particles stick together, leading to clumping,” he described. In contrast, rice is a “starch, making it able to hold onto water from the atmosphere preferentially over salt,” said Le. The fact can be easily witnessed when eating rice dishes like risottos, gumbos, fried rice, rainbow rolls, jambalaya, or rice cakes. When boiled and cooked, the chunky raw rice holds a lot of water and its grains inflate like tiny hot air balloons.

“When the humidity is high, water molecules in the air attach to the surface of salt crystals. Above a certain relative humidity, at what is called the ‘deliquescent point,’ there are enough water molecules at the surface of the salt crystal to actually dissolve the salt, forming a layer of saturated salt solution,” food scientists Richard W. Hartel and AnnaKate Hartel, write in their book Food Bites, as shared on Google Books. They added that when humidity goes down, some water rises in the air, leaving the salt to recrystallize. When this salt crystal comes in contact with other crystals, a “crystal bridge” forms between them. And when enough crystal bridges are formed, the salt clumps. In such a scenario, grains of rice can help by trapping water from the air and preventing salt from clumping.

However, this trick works best with white rice, as its starches are more exposed and therefore, promote better absorption. In brown rice, the bran covering the rice limits the grain’s ability to trap moisture. Apart from rice, kitchen staples like small beans, pasta, and macaroni can also prevent clumping in salt shakers, said Le. In another blog post, a chemist shared that pulses and coffee beans will also do the trick. For all those who like to have a little bit of extra salt in everything they eat, this trick will work wonders. Otherwise, as the Hartels described in their book, one will only keep on shaking the shaker and only sweat will come out, not salt.