Cooks living in humid climates are painfully aware of salt's tendency to absorb moisture and cake together in a solid lump. Modern table salt contains anti-clumping ingredients to inhibit this process, but it's not a perfect solution. Pure artisanal salts lack those additives and are even more prone to caking. Oddly, a simple and low-tech container called a "salt pig" is arguably the most effective way to keep your salt dry and loose.
As counterintuitive as it might seem, salt pigs don't provide airtight storage for your salt. In fact, they're the direct opposite. They're simple, open earthenware containers, with a mouth wide enough to easily reach in with your hand or measuring spoon. The opening is in front, so the top of the pig forms a protective shield that prevents debris and foreign objects from falling into your salt. It's the unglazed interior of the pig that prevents your salt from caking, despite being open to the elements. The porous pottery absorbs moisture from your salt, keeping it dry and free-flowing.
A Pinch at a Time
Pig-shaped salt pigs are certainly available if your taste runs to whimsy, but -- if you prefer to keep kitsch out of your kitchen -- they're not the only option. Traditional versions are typically formed as a simple cylinder, bent forward at the opening into a cowl shape. When you need to use salt, simply reach into the pig with your fingers and extract a pinch at a time. You may have noticed that this is how TV chefs typically season their foods, and it's because it gives you better control over your salt than using a shaker or grinder.