Production requirements, temperature and pressure of water and steam and cycle time.
Nozzle spray efficiency, external cleaning brushes, cleanliness reguirements and sterility of casks after washing and rotation/use of casks in trade.
The important parameters in the washing regime are:
The total spraying time in conjunction with adequate pressure.
The total time for which the temperature exceeds 82° C (180° F).
Suitable detergents should be used.
Efficiency of cleaning must be checked to ensure that cask washing is not a source of infection.
High levels of cask beer returns may be indicative of inefficient cask washing.
Range of Values
Microbiological examination of washed casks should ideally give zero cell count.
Water temperature is typically in the range 82° – 88° C (180° – 190° F) when using steam and 99° – 104° C (210° – 220° F) when not using steam
Water pressure is typically in the range of 5·5 – 7·6 bar g (80 – 110 psi), the exact value depending on the type of cask washer employed.
Steam pressure is typically 6·2 – 7·6 bar g (90 – 110 psi).
Holding time will depend on the number of stations but is typically 16 – 18 seconds.
The casks are drained and washed, shive hole downwards to prevent any washings running back into the casks
Cask interiors should be visually inspected at the end of the washing cycle, immediately prior to filling
Temperatures and pressures of water and steam are monitored
Sterility of washed casks is monitored
After washing each cask is sited for a final visual check of the cask interior, prior to immediate filling. Unacceptable casks (i.e. those with soiling, debris remaining or off-taints) are returned for washing and then re-examined
Casks with damaged interior surfaces or with off odours are set aside for repair or special treatments.
Washer cycle time should be checked
Nozzle spray efficiency is checked daily using a glass-ended cask and feeler gauges.