What You Need to Know
During proofing, Saccharomyces cerevisiae ferments glucose to carbon dioxide and ethanol, while lactic acid bacteria such as Lactobacillus sanfranciscensis produce lactic and acetic acids that lower dough pH and contribute sour notes. Malt α‑ and β‑amylases hydrolyze starch into fermentable sugars, enhancing yeast activity and crumb softness. The generated CO₂ expands the gluten network, and ethanol evaporates during baking, leaving characteristic volatile aromas.
The Science
Primary Reaction
Glucose → CO₂ + ethanol (yeast) and glucose → lactic acid (lactic acid bacteria)