We investigated the effect of treatments with different types of activated carbon on the concentration of free fatty acids (FFAs) in sake brewed using cerulenin-resistant sake yeast, which is known for its high ethyl caproate production ability. Residual FFA concentrations were lower in sake treated with steam-activated carbon than in sake treated with molecular sieving carbon and chemical-activated carbon. However, the FFAs could not be effectively removed from the sake even by steam-activated carbon.