Description
A controlled multi-phase fermentation process that simultaneously saccharifies rice starches and ferments sugars into alcohol.
Technical
Involves staggered additions of rice, koji (Aspergillus oryzae-inoculated rice), and water to maintain optimal yeast activity while preventing osmotic shock. Koji enzymes (α-amylase, glucoamylase) hydrolyze starch into fermentable sugars while Saccharomyces cerevisiae converts them to ethanol.
Culinary Significance
The foundational process for sake quality, determining alcohol content (18-20%), umami development, and aromatic complexity.
Science
Primary Reaction
Parallel saccharification (C6H10O5)n + nH2O → nC6H12O6 and fermentation C6H12O6 → 2C2H5OH + 2CO2
Parameters
Temperature
15°C optimal
10°C to 22°C range
Time
21-25 days
18 days – 32 days
Equipment