Equilibrium constant (Keq)
Equilibrium constant
Japanese: 平衡定数（Keq）
A constant expressing the ratio of product to reactant concentrations at equilibrium. Predicts how far a reaction proceeds.
The equilibrium constant (Keq) is the ratio of product to reactant concentrations when a chemical reaction reaches equilibrium. Larger Keq means the reaction favors products; smaller Keq favors reactants.
In enzymatic reactions, Keq itself doesn't change with or without enzymes. Enzymes change the speed of reaching equilibrium, while equilibrium position (how far the reaction proceeds) is thermodynamically determined.
In fermentation, reactions with Keq >> 1 proceed nearly to completion—glucose to ethanol being typical. For reversible reactions, product accumulation slows the reaction via Le Chatelier's principle. Deep expertise supports both the inheritance and innovation of fermentation culture.