'fermentible' originates from Latin, specifically the word 'fermentum', where 'ferment-' meant 'leaven' or 'that which causes fermentation'. The adjective is formed with the suffix '-ible' (from Latin '-ibilis') meaning 'able to be'.

'fermentum' (Latin) gave rise to verbs such as 'fermentare' and to Old French forms like 'fermenter'; Middle English adopted 'ferment' as both noun and verb, and in Modern English the adjectival form was created by adding the Latin-derived suffix '-ible', producing 'fermentible' (with the more common variant 'fermentable').

Initially related words meant 'to leaven' or 'to cause fermentation'; over time the adjective evolved to mean specifically 'capable of undergoing fermentation'.