Inactivation of Yeast


The Yeast Thermolizer deactivates yeast by heating.

Containing a high level of vitamin B and proteins, waste or surplus yeast is a valuable product which can be used after heat treatment. For thermal deactivation the yeast is heated to its deactivation temperature. The yeast flows through a special heat exchanger, then into a holding tube. Hot water or steam can be used as heating medium. In the holding tube the yeast is held at the deactivation temperature for a specified time. 10 seconds at 167°F (75°C) is generally sufficient to deactivate yeast. In this way, all the live cell membranes are ruptured.

For efficient energy use, the deactivation system can be designed as a two-stage system with a regeneration zone. The first step is energy recovery. The live yeast is heated as it flows in counter current to already deactivated hot yeast. Heat from the deactivated yeast is thereby returned to the process. In the second step it is warmed up to the target deactivation temperature by the heating medium.

Typical Technical Data

  • Capacity

    265 - 26,500 gal/h (10 - 1,000 hl/h)

  • Deactivation Temperature and Holding Time

    depending on product/application

  • Material

    1.4301/AISI 304; 1.4404/AISI 316L; etc.

  • Heating Medium

    hot water, steam as primary source

  • Cooling Medium

    glycol, ice water, ammonia, brine

  • Options

    heat recovery section
    booster pump


  • Constant deactivation, with highly accurate process control
  • Heat recovery for efficient energy use
  • Customized design; different automation levels