This Newsletter is concerned with the topic of PVPP-free beer stabilisation. In recent years PVPP has frequently been the focus of more or less well-researched
articles and reports. These have given rise to common questions such as “Do you use plastic for filtration too?” The market is, however, currently facing a fresh challenge in addition to this poor image:
Poor or no availability of PVPP.

Thanks to PVPP the majority of German breweries achieve a best before date of between five and eight months. But what alternatives to PVPP stabilisation are available within the confines of the German Purity Law? Combination of silica gel and bentonite (+ silica sol) Pure silica gel stabilisation (higher dosages)

Combination of silica gel and silica sol
1) Pre-stabilisation using bentonite (SodiBent SupraSodiBent Supra):
SodiBent SupraSodiBent Supra is a sodium bentonite (mainly consisting of the clay mineralmontmorillonite) which exhibits a strong swelling capacity.

In addition to adsorption of mainly medium and high-molecular proteins, polyphenols and anthocyagens are reduced by approximately 10%. Filtration stand time is also improved as it is used when piping the beer or during transfer to a buffer tank. A suspension of approximately 10% of the bentonite powder and water is left to prime for approximately four hours before use. The suspension is then dosed pro rata to the volume, preferably when piping. The dosages are between 30 and 60 g/hl. The sedimentation speed is around > 2m/day and can be assisted by the use of a silica sol (BrauSol Special).

Example 1: Combination of KiGel Sensitive, SodiBent Supra (bentonite) and Brausol Special (silica sol).

Advantage of combined pre-stabilisation with BrauSol Special and SodiBent Supra:

• Lower yeast load and lower turbidity values at the filter inlet
• Lower quantity of silica gel during final filtration, more room in the filter
• Improved filter stand times as a result of very well preclarified beer
• Stabilisation of tannin by SodiBent Supra

2) Pre-stabilisation with BrauSol Special
The high, negatively charged BrauSol Special silica sol reacts with the positively charged proteins in the beer. As a final reaction, the silica sol is restructured into a hydrosilica gel, so that it looks like a 3D net.

When BrauSol Special is added to the wort or beer, the SiO2 molecules link and are converted into an insoluble hydrogel. Together with turbidity-forming particles (12-160 kDa), it flocculates and deposits on the tank floor. The product’s speed of deposition is between 1.1-1.3 m/day.

It can be used at various stages of beer production:

• In the hot area (use in the whirlpool; 20-40 ml/hl)
• Dosage in the cooled wort (during cooling; 20-40 ml/hl)
• Addition to young beer (when piping, 20-40 ml/hl)

Example 2: Combination of KiGel Sensitive and BrauSol Special silica sol

Advantage of pre-stabilisation with Brausol Special:

• Lower yeast load and lower turbidity values at the filter inlet
• Improved filter stand times as a result of very well pre-sclarified beer

Summary:
It is possible to produce stable beers without PVPP. Protein alone can be stabilised, or tannins and proteins in combination with a bentonite.

Summary of the advantages:

• Current better availability of silica gels than PVPP
• Reduced stabilisation costs
• No discussion about “plastic in beer”
• More room in the filter for flocculation aids

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