A professional who operates battery of stationary or rotary steam digesters to cook wood chips with soda ash or acid to make pulp for use in manufacture of paper and insulation board. Respnsibilities include:

• Signals digester-operator helper to charge digesters with specified amounts of chips and chemicals.
• Turns valves or moves panel controls to admit steam into digesters, to raise temperature and pressure within specified limits, and to start rotary digesters.
• Monitors temperature, flow, and pressure gauges and charts to ensure that chips are cooked according to specifications.
• Tests samples of digester liquid by titration or standard color chart to determine completion of cooking process.
• Opens valves of stationary digester to blow cooked pulp into pit, or pulls lever to tip rotary digester and dump contents.
• Compiles production records.
• May be designated according to process as Cooker, Soda; Cooker, Sulfate; Cooker, Sulfite.