A professional who tends vats in which fats or vegetable and animal oils are processed into glycerin and fatty acid. Respnsibilities include:

• Pumps specified amount of fat or oil into vat and admits prescribed quantity of sulfuric acid from storage tank.
• Observes gauges and thermometer and turns steam valves to boil contents of vat.
• Pumps oil or fat to second vat and adds specified amount of distilled water and Twitchell's reagent.
• Starts agitator in vat and turns steam valves to boil mixture for prescribed time.
• Observes mixture through sight glass in pump line and turns valves to transfer fractions of product having different color and density to respective storage tanks.
• Records shift production, materials used, and heating and agitating time.