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Physical Stabilisation

ensuring haze-free, longer lasting beer

Physical stabilisation is the process of preventing hazes and deposits from forming after the beer has been packaged. This can be achieved by removing constituents that will eventually lead to haze formation, such as certain proteins and polyphenols, or by accelerating the formation of hazes and deposits so that they can be removed prior to packaging.

Typical methods of removing haze precursors are the addition of fining agents, or filtration using adsorptive powders such as diatomaceous earth (DE) or polyvinylpolypyrrolidone (PVPP). The porous screens, sheets or candles that are used to support the powder as it is dosed into the beer will always allow some powder through and trap filters should be positioned downstream to prevent this powder from reaching final storage and packaging. Alternatively, the DE and PVPP may be incorporated into a cellulose fibre matrix that is then cut into preformed sheets or assembled into stacked disc (or lenticular) cartridges. This may be a more convenient method of stabilisation and produces a higher degree of clarity to the beer.

Trap filtration is usually achieved using clarification filters with retention ratings between 5μm and 15μm for DE trap and 5μm and 25μm for PVPP. Medium and fine grades of sheet and lenticular filters will provide high product clarity and good physical stability.

Once the beer has been physically stabilised, further treatment usually involves assuring microbiological stability and polishing to provide bright clarity.

• Strong, washable cellulose sheets support powder precoat in plate and frame filter presses.
• Trap filters remove small quantities of powder released from upstream processing and protect the process in the event of major bed collapse.
• Adsorptive filter sheets and lenticular cartridges provide clarification and physical stabilisation.
• Designs that optimise performance in forward flow and backwashable applications.