A professional who controls fermentation process of sweet or sour mash inoculated with yeast to produce fermented mash for use in distillation of distilled liquors. Respnsibilities include:

• Pumps specified number of gallons of cooked mash and yeast into fermentation tank, simultaneously, to ensure that mash and yeast are thoroughly mixed together.
• Opens valves to admit specified number of gallons of water into mixture, according to formula.
• Opens valves to circulate steam through coil pipes in tank to heat mixture to prescribed temperature.
• Turns valves to admit and control air pressure that agitates mixture as it ferments or to accelerate chemical reaction of yeast.
• Observes gauges or dials to ascertain that prescribed temperature and gas pressure are remaining constant in tank.
• Tests mash at prescribed intervals to determine temperature and specific gravity (proof), using thermometer and alcohol-proof hydrometer.
• Compares test results with standard charts to determine when mixture is fully cooked.
• Regulates steam, air, and gas pressure in tank to ensure that chemical reaction of yeast and fermentation process is taking place, according to formula.
• Pumps sour mash into cistern tank, preparatory to distilling.
• Cleans tanks by rinsing them with water.