impetus — a moving force; impulse; stimulus: The grant for building the opera house gave impetus to the city's cultural life.
incentive — something that incites or tends to incite to action or greater effort, as a reward offered for increased productivity.
motivation — the act or an instance of motivating, or providing with a reason to act in a certain way: I don't understand what her motivation was for quitting her job. Synonyms: motive, inspiration, inducement, cause, impetus.
stimulant — Physiology, Medicine/Medical. something that temporarily quickens some vital process or the functional activity of some organ or part: Adrenalin is a stimulant for the heart. Compare depressant (def 4).
agitator — If you describe someone involved in politics as an agitator, you disapprove of them because of the trouble they cause in organizing campaigns and protests.
goad — a stick with a pointed or electrically charged end, for driving cattle, oxen, etc.; prod.
impulse — the influence of a particular feeling, mental state, etc.: to act under a generous impulse; to strike out at someone from an angry impulse.
incendiary — used or adapted for setting property on fire: incendiary bombs.
incitation — to stir, encourage, or urge on; stimulate or prompt to action: to incite a crowd to riot.
reactionary — of, pertaining to, marked by, or favoring reaction, especially extreme conservatism or rightism in politics; opposing political or social change.
synergist — Physiology, Medicine/Medical. a body organ, medicine, etc., that cooperates with another or others to produce or enhance an effect.
spark plug — a device designed to fit in each cylinder of a gasoline-powered internal-combustion engine and to produce the electric spark for igniting the mixture of gasoline and air.
bacteria — Bacteria are very small organisms. Some bacteria can cause disease.
bacterium — Bacterium is the singular of bacteria.
barm — the yeasty froth on fermenting malt liquors
ebullition — a seething or overflowing, as of passion or feeling; outburst.
leaven — a substance, as yeast or baking powder, that causes fermentation and expansion of dough or batter.
leavening — a substance, as yeast or baking powder, that causes fermentation and expansion of dough or batter.
mold — loose, friable earth, especially when rich in organic matter and favorable to the growth of plants.
simmer — to cook or cook in a liquid at or just below the boiling point.
yeast — any of various small, single-celled fungi of the phylum Ascomycota that reproduce by fission or budding, the daughter cells often remaining attached, and that are capable of fermenting carbohydrates into alcohol and carbon dioxide.
catalyst — You can describe a person or thing that causes a change or event to happen as a catalyst.
ferment — Also called organized ferment. any of a group of living organisms, as yeasts, molds, and certain bacteria, that cause fermentation.
