Ever wondered why on earth we use the phrase “worth their salt” to indicate someone is valuable and worthwhile in their position? After all, salt is inexpensive and abundant. You can buy a big box of the refined stuff for a few bucks at your local grocer. So what gives?
Salt may be readily accessible and easily afforded these days, but that wasn’t always the case. Salt is essential to life, and for much of recorded history, salt has been incredibly valuable and often difficult to come by. (Even though much of the world is covered in salt water, extraction was not a simple or efficient task without modern technology.) Its value was tied to the fact that salt was used to preserve food before artificial refrigeration was invented. AskHistory.com says, “In this way, salt came to represent power; without it, armies couldn’t travel great distances and explorers couldn’t sail to new lands because their provisions would spoil.” The more salt an empire (or person) had, the more advantages in the quest for power. Salt also carries significance in many religions and cultures, adding to its perceived value.
Because of this multifaceted value, salt became an important commodity and even currency. There is some debate about whether or not ancient Roman soldiers were actually paid in salt or given an allowance for purchasing it, but that compensation was known as a “salarium,” which gave rise to the modern word “salary.” “Salarium” is Latin, using the root word “sal,” meaning salt. So, someone who is skilled at their vocation is earning their pay and hence “worth their salt.”
There is a more harrowing association with this idiom as well. According to HowStuffWorks.com, salt was traded for slaves, and that is the true origin of the phrase. This is a less-cited possibility, but one that should be noted.
So there you have it. “Worth their salt” was once a rather literal assessment of someone’s labor value. Nowadays, we typically use this colloquialism in the negative or as an expected standard, i.e., “any doctor worth their salt would…” instead of as praise for competency. Regardless, we’re going to call that a good thing, based solely on the fact that our bank accounts are full of money and not seasoning.