Microorganisms Flashcards
What is Koji mold and why is it essential in sake production?
Koji mold (Aspergillus genus) produces enzymes that break rice starch into sugars, enabling yeast to ferment them into alcohol and flavor compounds.
What are the three types of Koji mold?
- Yellow Koji – for sake, strong saccharification power.
- Black Koji – used for Awamori, strong Saccharification, citric acid.
- White Koji – mutation of black Koji, used for shochu, strong Saccharification, citric acid.
What is sake yeast scientifically called, and what does it do?
Saccharomyces cerevisiae; converts sugars into alcohol and carbon dioxide. It works even at low temperatures and produces rich aromas.
What is Kyokai yeast?
Standardized sake yeast distributed by the Brewing Society of Japan. Kyokai No.7 is widely used; No.9 is known for fruity ginjo sake.
Where else are sake yeasts developed besides the Brewing Society of Japan?
R&D institutes in each prefecture develop unique yeasts to improve local sake and support regional branding.
What are wild yeasts in sake brewing?
Naturally occurring yeasts (e.g., flower yeasts like Hanakobo) selected for their aroma and diversity, often used in experimental or craft sakes.
What role do lactic acid bacteria play in sake brewing?
They acidify the mash, preventing unwanted microbial growth. Some harmful types (hiochi bacteria) can spoil sake but are removed by heat pasteurization.
What are nitrate-reducing bacteria used for in kimoto sake?
They produce nitrous acid early in fermentation to suppress harmful microbes, paving the way for lactic acid bacteria to dominate later.
