Lesson 5 - Clarification – Centrifugation SAQ

**Answer BOTH parts of this question:

a)    List four advantages and disadvantages of running a centrifuge in your brewery.

b)    What factors must a brewer control in a centrifuge system to maintain optimum quality?

Response:

Part a)

Advantages:

1)    Centrifuges have small space requirements

2)    They are hermetically sealed by fitting seals on all moving parts, to avoid oxygen ingress

3)    Rapid and efficient clarification before further processing steps

4)    Low beer loss in comparison to natural sedimentation

Disadvantages:

1)    High electrical demand

2)    Centrifuges are loud and require a dedicated room

3)    Centrifuges are complex and have high maintenance costs

4)    Mechanical shear forces generated during centrifugation may break-up of large particles, which may increase the concentration of fine haze particles

Part b)

There are key quality considerations a brewer must control during centrifugation. These can be summarised as follows:

• Oxygen exclusion – a hermetically sealed process must be maintained to avoid any risk of oxidation which could lead to product staling

• Clean and sterile environment – CIP regimes must be adhered to avoid the risk of microbiological contamination

• Minimal beer temperature rise – centrifuges generate much thermal energy and to minimise temperature pick-up, there should be a constant feed of beer onto the centrifuge. Repeated stop and start scenarios also cause beer temperature increase.