In a Word: Fermenting or Fomenting?

Even the best writers have trouble deciding whether to use ‘ferment’ or ‘foment.’

An angry man with steam coming out of his ears.
rangizzz / Shutterstock

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Managing editor and logophile Andy Hollandbeck reveals the sometimes surprising roots of common English words and phrases. Remember: Etymology tells us where a word comes from, but not what it means today.

Presidential candidate Joe Biden sent many people rushing to the dictionary on Monday when he accused the president of fomenting violence. Foment isn’t a very common word; is it the right one to use here? What does it mean? And is it anything like ferment?

Foment has long been used to mean “incite” or “stir up,” but it began its life in English in a more mundane way. Though some usage mavens recommend restricting the word ferment to the culinary sphere, it has long been used metaphorically to mean “agitate, cause unrest,” making it as valid and useful as foment in some political discourse.

These two near-synonyms can confuse even the best writers, but there are some key differences in how they should be used.

But first, a little word history:

Like many English culinary terms, ferment was adopted from French, but it goes back to the Latin fermentum, “leavening agent (such as yeast).” When something ferments, it changes organically: bread dough rises, bubbles rise to the top of a brewing ale. Though the word entered English only in the “leavening” sense in the late 14th century, the active change of fermentation opened it up to metaphorical meanings — “agitate, cause unrest” and “to develop organically” — during the English Civil War in the mid-17th century. Today both the literal and metaphorical uses are well-attributed.

You might call foment a physical therapy term — if the phrase physical therapy had been in use half a millennium ago when foment appeared. It too traces back to Latin, to fomentum “warm application, poultice.” When foment found its place in English in the late 14th century (again via French), it referred to the therapeutic use of heat — especially through hot liquids. For example, after a long, hard day, a worker might be advised to foment his sore muscles. But muscles aren’t the only thing that can get heated up, and by the early 1600s, foment also referred to heating up a crowd, that is, inciting or instigating them. Today, its early therapeutic sense is more or less obsolete.

Fermentum and fomentum — I wouldn’t be surprised to learn that ancient Romans confused these words as often as we confuse their Modern English equivalents. But it’s more difficult these days because the metaphorical meanings of ferment and foment can, at times, seem to apply equally to the same situation, and one word may seem more or less appropriate depending only on which side of an argument you fall on.

But there are a few guidelines that can help you find the right word in your own writing:

  • Foment always has a negative connotation. No one ever foments peace, love, and understanding.
  • Foment is always a transitive verb, meaning it requires an object. Someone foments something, or something is fomented by someone, but something doesn’t foment itself.
  • Foment implies an active participant, an agitator. If you’re describing a change — rising political unrest, for example — without someone actively aiding it, you probably want ferment.
  • The metaphorical sense of ferment doesn’t need that active participation. An idea or an urge might ferment (“develop naturally or unaided”) in a person before exploding to the surface.
  • Which is not to say that ferment can’t also have an active fermenter, though this usage is probably best restricted to writing about food and drink.
  • If you’re still confused, remember that you don’t have to use either of them in your own writing. English has a wide array of synonyms to choose from.

Featured image: rangizzz / Shutterstock

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  1. Interesting, timely look at these two words. I believe the former Vice-President was quite correct in his accusations, with a lot more material just since Monday. Foment IS a good and accurate word, although I’d probably stick with inciting instead. ‘Ferment’ (regarding the yeast) on the rare occasions I make home made bread.


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