A professional who controls equipment to prepare mixture of mash and yeast for use in manufacture of distilled liquors. Respnsibilities include:

• Weighs specified quantities of rye and malt meal, depending upon amount of yeast required, and dumps them into yeast tub (cooker) filled with specified amount of water.
• Opens valves to admit steam that circulates through coil pipes in tub and cooks mixture.
• Starts revolving blades in tub to agitate mixture as it cooks.
• Observes temperature gauges and increases or decreases steam pressure to maintain constant temperature as mash cooks.
• Pours yeast culture into cooked mash and mixes mash with revolving blades.
• Stops revolving blades when mash and yeast are thoroughly mixed.
• Tests mash to determine temperature and specific gravity (proof), using thermometer and hydrometer, and records results.
• Observes gauges and increases or decreases steam to ensure that mash ferments at constant temperature.
• Notifies fermentation operator when mash is ready to be pumped into fermentation tank.
• Removes sample of mash for laboratory analysis.