Function of Auxiliary Finings

General Considerations

• Axiliary fininqs aid the action of isinglass finings by enhancing the total negative charge, especially when contribution by yeast is low. This improves the electrostatic interaction between proteins and isinglass finings. Beers fine more quickly because of the larger floc size.
• Auxiliary finings are available in solution as acidified polysaccharides, silicates, alginates and formulated blends.
• Factors which need to be considered are the type of auxiliary finings, dosage rate, storage temperature and conditions, time of addition, fining performance, yeast count prior to fining and compactness of sediment (see Topic 29).

Range of Values

• Sulphur dioxide content of liquid auxiliary finings is typically between 200 and 300 mg per litre.
• Solutions of auxiliary finings should be visually bright prior to use.
• Yeast counts are typically 0·5 x 106 – 2 x 106 cells per ml with a mean of 1·0 x 106 cells per ml.
• The dosage rate of auxiliary finings is typically 0·9 – 3·5 ml per litre (¼ – 1 pint per barrel), but is related to the isinglass dosage rate and depends on compactness of the sediment.

Operational Protocols

• Liquid auxiliary finings are stabilised with sulphur dioxide and stored in inert containers at ambient temperature There must be adequate ventilation in the storage area because levels of sulphnr dioxide particularly on delivery can be high.
• Addition is made in-line through a dosing pump as beer is transferred from fermenting vessel to racking tank or directly to tank or cask
• Addition of alginate auxiliary finings is made at least 4 hours before addition of isinglass finings. Due to the rapid action of silica based auliliaries they can be added either pre- or post-isinglass finings. The actual time of addition is determined by experience.

Measurement Protocols

• Every batch of finings should be inspected visually and examined for infection by micro- organisms.
• Fining action is monitored by making the equivalent addition of finings to appropriate samples of beer and noting daily the size of flocs, speed of fining action and clarity of fined sample
• A nine gallon cask is fined and stillaged in the sample cellar for a larger scale production check on the fining performance (see Topic 29).
• Finings contribute to sulphur dioxide levels in beer The levels of sulphur dioxide in samples of fined beer should be measured. Auxiliary finings supplied by Murphy & Son Ltd. will add in the order of 0·25 – 1 ppm SO2 to the beer at typical addition rates.