ferment

ferment — verb

1. When yeast or bacteria act on the sugars found in items such as fruit, milk, or

1.verbtransitive / intransitiveB2
Definition

When yeast or bacteria act on the sugars found in items such as fruit, milk, or grain, the substance changes chemically — the sugars turn into alcohol or acids, and bubbles or heat often appear. People also ferment foods on purpose to make products such as wine, beer, yogurt, or kimchi.

Example

Hao left grape juice in a warm jar, where it fermented into wine within days.

intransitive: ferment + into [product]

To make kimchi, Marta fermented the cabbage with salt and chili for several weeks.

transitive: ferment [food] with [ingredients]

Common collocations
  • ferment slowly / rapidly / naturally
  • ferment into wine / beer / yogurt / kimchi
  • ferment with yeast / bacteria / salt
  • ferment for days / weeks / months
  • leave something to ferment
Synonyms
  • break down

    more general; does not specify the role of yeast or bacteria

  • sour

    narrower, usually describing milk or dairy spoiling

  • cultivate

    implies human intention to grow bacteria or yeast, not a natural process

Antonyms
  • preserve

    keeping food fresh by stopping fermentation (e.g. pickling with vinegar or refrigeration)

Grammar Patterns

ferment (intransitive — food/drink changes chemically)

ferment + noun phrase (transitive — you cause the change)

Usage Note

Common in cooking, baking, and brewing contexts. The transitive form (you ferment something) is typical when describing a recipe or industrial process; the intransitive form (something ferments) describes a natural or spontaneous process.

Common Mistakes

The fruit decayed in the sun.
The fruit fermented in the warm jar.
'ferment' is a controlled or natural chemical change that produces useful products (alcohol, yogurt, bread); 'decay' means rot and spoilage without a useful result.

2. If a situation or group of people ferments, feelings of anger, excitement, or di

2.verbtransitive / intransitiveC1
Definition

If a situation or group of people ferments, feelings of anger, excitement, or disagreement build up and grow stronger over time, often leading to change or conflict. To ferment something means to cause this kind of emotional or social unrest.

Example

Anthony noticed that the ideas fermenting among the workers could lead to a strike.

intransitive: ideas / feelings ferment among [group]

Amani's speech about inequality fermented a wave of protest across the university.

transitive: speech / event fermented [response]

Common collocations
  • ferment for months / years
  • ideas / feelings / discontent / anger ferment
  • ferment rebellion / protest / revolution
  • ferment among [a group of people]
Synonyms
  • foment

    only transitive; strongly implies deliberately causing unrest

  • seethe

    intransitive only; suggests a hidden, barely controlled anger

  • simmer

    intransitive only; suggests unrest building slowly below the surface

Antonyms
  • calm

    when emotions or a situation calms down, the agitation subsides

  • subside

    to become less intense; the opposite of building up

Grammar Patterns

ferment (intransitive — situation/feelings become agitated)

ferment + noun phrase (transitive — cause agitation, e.g. ferment discontent)

Usage Note

Frequently found in formal writing about history, politics, or social movements. The intransitive form (discontent ferments) emphasises a slow, underground buildup; the transitive form (to ferment rebellion) is closer in meaning to 'foment'.

Common Mistakes

The students were fermenting in the classroom.
The students' anger fermented over weeks of unfair treatment.
'ferment' as a verb of unrest needs an abstract subject (anger, ideas, discontent), not a person as the subject.

ferment — noun

Word family

  • fermentation
    nounB2
  • fermented
    adjectiveB2
  • fermenting
    adjectiveB2
  • fermentable
    adjectiveC1
  • non-fermented
    adjectiveC1
  • fermenter
    nounC1

Synonym discussion

Sense: noun/1

All four words describe a state of disorder or change, but they differ in scope and connotation. 'Turmoil' is the most general word for confusion and chaos, used for both personal situations and large-scale events ('His mind was in turmoil'). 'Upheaval' suggests a violent or dramatic disruption that overturns existing structures, often sudden ('The political upheaval after the coup'). 'Unrest' focuses more narrowly on dissatisfaction and protest, typically among a group of people ('Labour unrest spread across the factories'). 'Fermentation' is the literal chemical noun and is rarely used figuratively; when it is, it emphasises a slow, organic process of change rather than a sudden crisis ('a period of intellectual fermentation'). 'Ferment' as a noun sits between 'turmoil' and 'upheaval' — it implies an active, often creative process of change in a society or group, not just chaos. For example: 'The 1960s were a decade of artistic and social ferment', not merely 'turmoil' or 'unrest'.

turmoil ↗upheavalunrest ↗fermentation

Common collocations

Nouns

Adverbs

Phrases

  • in a state of ferment
  • leave something to ferment
  • a period / decade of ferment
  • ferment of [activity / ideas / change]

Prepositions

Etymology

LatinOld FrenchEnglish

The word 'ferment' entered English in the 14th century from Old French 'ferment', which came from Latin 'fermentum' meaning 'leaven, yeast, agent that causes rising'. The Latin root 'fermentum' itself comes from 'fervēre', meaning 'to boil, to seethe' — because the bubbling action of fermentation reminded speakers of boiling water. The literal meaning (food or drink changing chemically) was used from the earliest records. By the 17th century, writers had begun using 'ferment' figuratively to describe social or political unrest, drawing on the image of a liquid boiling or bubbling up from within — an apt metaphor for a society in turmoil.