Why the corn has to be chewed
Corn kernels store much of their energy as starch: long chains of sugar molecules that ordinary brewing yeast cannot use directly. Chewing breaks the kernels into smaller pieces and mixes them with saliva. Saliva contains amylase, an enzyme that snips some starch chains into shorter sugars that yeast can ferment.
The mouth is doing a small version of a job that modern brewers usually handle with heat and enzymes. In conventional brewing, prepared grains are soaked under controlled conditions so starch is converted into fermentable sugars before yeast is added. With chewed corn, saliva supplies part of that conversion work.
From sugar to alcohol
Once the chewed corn is mixed with liquid and allowed to ferment, yeast consumes accessible sugars. It converts them mainly into alcohol and carbon dioxide. The yeast is not turning the corn’s starch directly into alcohol; the starch first has to be broken down into sugars it can use.
That distinction also explains why chewing does not make every bit of corn fermentable. Saliva can convert only some of the starch, and the result depends on how the mixture is prepared and fermented. The striking part is the handoff: a human enzyme begins unlocking the corn’s stored energy, and yeast completes the transformation.
