Lab Technique · Entry 23 of 42
Fermentation
Microbial metabolism converting sugars into gas, acid, or alcohol.
How it works in the lab
Fermentation is run in labs from small flasks to industrial bioreactors, where pH probes, dissolved-oxygen sensors, and temperature control keep the microbes in their ideal range while they convert sugar into a target product, whether that is ethanol, an antibiotic, or insulin made by engineered yeast. Pasteur showed that fermentation is caused by living organisms and that excluding contaminants changes everything, founding modern microbiology. Monitoring gas production, acidity, and growth over time turns a living process into measurable data.
Research Findings
The technique at the heart of Pasteur's foundational 19th-century fermentation studies.
Skills you gain in the lab and kitchen
- Reading dough rise as a measure of fermentation
- Controlling temperature to speed or slow yeast
- Timing fermentation to peak activity
- Managing a mixed yeast and bacteria culture
- Connecting gas production to leavening
How it shows up in baking
Yeast fermenting bread dough produces carbon dioxide that inflames the gluten network and alcohol and acids that build flavor, and bakers read the rate by how much the dough rises in an hour. A sourdough starter ferments with wild yeast and bacteria, producing the lactic and acetic acids behind its tang. Both settings treat a metabolic process as something to be steered by feeding, temperature, and time.
Recipes that demonstrate this technique
Each card shows exactly where the technique appears inside that recipe's method.
Picarones
Letting the squash-based batter ferment slightly before frying, producing the characteristic ring shape and texture.
Injera
Fermenting a teff-flour batter over several days, developing the sour flavor and characteristic bubbled surface.
Puff Puff
Letting a yeasted batter rest until visibly bubbling before frying.
Bofrot
Timing how long the batter is left to rise before frying, which directly controls texture.
Mandazi
Letting the spiced, yeasted dough rise before it's fried in hot oil.
Baked Char Siu Bao
Proofing a yeasted dough around a pre-made filling before its final bake.