ABSTRACTEffects of residual air were evaluated on the heating rates of a convectionheating product processed in a continuous rotary sterilizer. Heat penetration tests were conducted in a Steritort at various reel speeds (1‐10 rpm) and air overpressures (0‐69.0 kPa) using 211 × 300, 300 × 407 and 603 × 700 cans containing Washington white beans in brine. Sterilization times calculated by Ball's formula method were longer for test cans processed with overpressure than those processed with no overpressure. Maximum reduction in calculated lethality for 69.0 kPa air overpressure was 15.2% for 211 × 300 and 300 × 407 experiments and 49.4% for 603 × 700 experiments. For each can size and reel speed, average process time was a linear function of ove