“Both sides are just trying to ferment a war,” a blog posting said of the situation in the Middle East. That gives rise to the question of how “ferment” and “foment” differ.
They come from similar words meaning “cherish,” “warm,” or “boil.” How they’re used, though, can be anything but warm and fuzzy.
Webster’s New World College Dictionary, fifth edition, says “foment” means “to treat with warm water, medicated lotions, etc.,” and “to stir up (trouble); instigate; incite.” “Ferment,” on the other hand, means “a substance or organism causing fermentation, as yeast, bacteria, enzymes, etc.,” or “a state of excitement or agitation.”
“Ferment” is seen most often, in differing contexts. Its verb form makes beer; its noun form is the result of someone “fomenting” or “fermenting.” Yes, that’s right: “Both sides are just trying to foment a war,” and the result is “ferment in the Middle East.” One noun form of “ferment” is, um, “ferment.” Another, of course, is “fermentation,” though that usage is mostly restricted to the excitement that comes from the yeast or bacteria.
WNW5 lists “foment” only as a verb. The Oxford English Dictionary says “foment” started life as a noun in the 16th century, though it quickly became a verb meaning “to incite,” or “to rouse.” The OED notes that “foment” has kept the original “cherish” sense in some contexts: “To cherish, cultivate, foster; to stimulate, encourage, instigate (a sentiment, belief, pursuit, course of conduct, etc.), esp. in a bad sense.”
The main noun form of “foment” is supposed to be “fomentation,” but, says Garner’s Modern American Usage, “some writers want to revive foment as a noun.” That “poor usage,” Garner’s continues, perhaps “arises from confusion with ferment (= agitation).” Because “fomentation” is rarely seen, Garner’s says, “foment, as a noun, ought to be considered a needless variant.”
Garner’s doesn’t much like the noun use of “ferment,” either. It puts the use of both “ferment” and “foment” instead of “fomentation” at Stage 2 of the five-stage Language-Change Index, or “widely shunned.”
There’s one place where “foment” and “ferment” peacefully coexist, and, not surprisingly, it involves alcohol. The place where the yeast “ferments” is called the “fomenter.” And if you’ve ever been near a “fomenter” of “fermenting” beer or other liquid, you can feel its warmth. Maybe it even incites a thirst.
Merrill Perlman managed copy desks across the newsroom at the New York Times, where she worked for twenty-five years. Follow her on Twitter at @meperl.