The cooling rate should be sufficient to control the flocculation and settling of yeast to give the desired yeast count at rack.
The rate of cooling depends on:
- Flocculation characteristics of the yeast.
- Fermenter design, i.e. square or cylindroconical.
Range of Values
- Initial beer temperature is usually 19° – 22° C (66° – 72° F).
- The temperature of cooled beer is typically 12° – 14° C (54° – 57° F).
- Typical rates of temperature fall are 1° C (2° F) every 8 hours in squares, and 1° C (2° F) every two hours in cylindroconical vessels
- The ‘Cleansing’ period in squares is typically 2 – 3 days.
- The temperature of the beer should be measured every 4 – 6 hours and the flow rate of coolant adjusted accordingly.
- The flow of coolant is preferably automatically controlled
Temperatures should be measured as far away as practicable from the attemperators.