What You Need to Know
Yeasts convert fermentable sugars to ethanol, followed by lactic acid bacteria producing lactic acid and acetic acid bacteria oxidizing ethanol to acetic acid. The pH drops from ~6.0 to ~4.0, enabling oxidative degradation of catechins to theobromine and the formation of volatile esters that contribute to chocolate aroma.
The Science
Primary Reaction
Sequential microbial metabolism of sugars to ethanol, lactic acid, and acetic acid, coupled with oxidative degradation of catechins and formation of flavor precursors