Geosmin-producing Streptomyces may cause the imbalance ofmicrobial flora seriously deterioratthe liquor aroma.The aim of this study is to identify the key factors restricting geosmin production in the liquor-making process.The influence of the main liquor-makingvariables(temperature,water content,ethanol content,pH) on the growth and metabolism of geosmin-producing Streptomyces were investigated.The results showedthat the yield of geosmin was positivelyrelated with the biomass and growth rate of the Streptomyces cells.The most suitable temperature for thegrowth of Streptomyces was 30℃,andthe optimum water content was 50%.The growth of geosmin-producing Streptomyces iscompletely inhibited at the alcohol content of over 10% vol.Moreover,Streptomycescan grow rapidly in the neutral and alkalescent(pH7-8) environment,whileit is severelyinhibited in the acidic environment(pH3-5) reduce geosmin production.The above discoveries provide reliable theory to control the earthy off-flavor in Chinese liquor.