Lesson 3 - Wort Clarification Technology and Process Control SAQ

*You have identified the need to improve wort clarification. What design and operational factors would you focus on?

Response:

The objectives of wort clarification are:

• Separate trub and spent hops from wort
• Produce wort of the required clarity
• Remove and dispose of trub and spent hops
• Minimise thermal load
• Minimise heat derived colour and flavour formation
• Minimise carry-over of foam negative compounds (e.g. lipids and fatty acids)
• Minimise time taken

To ensure successful wort clarification we need the size of the trub flocs to be, 5-10 mm in diameter. Floc size and the amount of trub formed is checked using Imhoff cones.

The use of processing aids can improve floc sizes and enhance separation effectiveness. Imhoff cones can also be used to determine the rate that achieves the best results.

It is important to minimise and standardise the stand time (duration) in the wort clarification vessel. This affects colour and flavour pick up and the effectiveness of solids removal.  

We must also standardise hop additions; any changes here will affect the effectiveness of the wort clarification system, as the system is designed to process specific hop products and hopping rates.

We must ensure that wort flow rates and velocities are correct as these affect whirlpool and centrifuge operation and the compaction of the filter bed in a hop back. Excessive velocities risk breaking up trub particles.

In terms of design factors, low shear pumps, sweeping bends and the absence of restrictions minimise shear on trub particles. All equipment must be designed to work with the beer being brewed and be maintained as recommended by the manufacturer.

We also need to ensure that upstream processes are effective and raw materials are fit for purpose.