Q: Why “salt” when we “take something with a grain of salt”? Is the salt to counteract something sweet?
A: The use of “with a grain of salt” to mean with caution or skepticism first appeared in early 17th-century English as a translation of cum grano salis, a modern Latin expression coined a century earlier.
The earliest written example of cum grano salis that we’ve seen is in a Latin treatise by a French legal scholar who uses it to describe a clause attached to a gift:
“ex parte altera excedit quod intelligatis cum grano salis” (“on the other hand it exceeds what is understood with a grain of salt”). From Tractatus de Viribus Iuramenti (A Treatise on the Strength of the Oath), 1502, by Antonius de Petrucia (Antoine de Peyrusse).
And here’s another early sighting: “Sed caute & cum grano salis (utaiunt) legendus est, quia intricatus facile legenti errorem obijcit” (“It should be read cautiously and with a grain of salt, as they say, because it is easy to present an intricate error to the reader”). From Compendium Sive Breviarium (1514), a brief history of the Franks, by Johannes Trithemius, a German Benedictine abbot.
“Why salt?” you ask. Well, the reason for “salt” here is uncertain, but the earliest English example of the usage that we’ve found suggests that it comes from salting food to make it taste better:
“The terms of Divinitie are to be taken into the mouth, as the Canonists [canon lawyers] speak, cum grano salis, with a grain of salt, that is, wisely tasted, and understood: otherwise, they will not prove good nourishment.” From Experience, Historie, and Divinitiem (1642), by Richard Carpenter, a vicar of Poling in Sussex.
The first English example in the Oxford English Dictionary was recorded a few years later in a biblical commentary on Revelation 6:11. The commentator says Christian martyrs would undoubtedly be aware of those still to be martyred and speak to God for them, then adds, “But this is to be taken with a grain of salt.” From A Commentary or Exposition Upon All the Epistles and the Revelation of John the Divine (1647), by John Trapp, an Anglican theologian.
The first-century Roman philosopher Pliny the Elder, writing in classical Latin, uses a similar phrase literally for an ingredient in a recipe: addito salis grano (“with the addition of a grain of salt”).
In his encyclopedic, 37-volume Naturalis Historia, he describes a poison antidote found among the belongings of Mithridates VI, ruler of the Hellenistic Kingdom of Pontus, after his defeat by the Roman General Pompey in 66 BC:
“in sanctuariis Mithridatis, maximi regis, devicti Cn. Pompeius invenit in peculiari commentario ipsius manu conpositionem antidoti e II nucibus siccis, item ficis totidem et rutae foliis XX simul tritis, addito salis grano: ei, qui hoc ieiunus sumat, nullum venenum nociturum illo die. contra rabiosi quoque canis morsum a ieiuno homine commanducati inlitique praesenti remedio esse dicuntur.”
Translation: “After the defeat of that mighty monarch, Mithridates, Gnaeus Pompeius found in his private cabinet a recipe for an antidote in his own handwriting; it was to the following effect: Take two dried walnuts, two figs, and twenty leaves of rue; pound them all together, with the addition of a grain of salt; if a person takes this mixture fasting, he will be proof against all poisons for that day.”
Was the salt added to the recipe to make the concoction more palatable? We think that’s possible, though you might take our explanation with a grain of salt.
Usage note: Although cum grano salis was originally translated as “with a grain of salt,” the usual expression now in British English is “with a pinch of salt,” a version that first appeared in the 19th century. Here’s an early example: “what men say of a lovely woman is generally to be taken with a pinch of salt!” From Puck (1870), a novel by Ouida, pseudonym of the English novelist Maria Louise Ramé.