Brewery assessment and evaluation.

Hahn, C.W.

Abstract
A remedial programme was developed and implemented at seven breweries to correct manufacturing faults which were creating inconsistencies in national brands. The brewery inspection tackled four main areas, taste samples, brewhouse operations, cellar operations and additive and recycle stream operations. Almost daily tasting was established of malt, water, CO₂ (in distilled water), diatomaceous earth slurry, sweet and hopped worts and finished beer. Several brews were carefully monitored in the brewhouse noting mashing, lautering, raking, boiling and whirlpool operation. Cellar operations studied were wort oxygenation, yeast pitching, CIP operations, oxygen pickup during beer transfers and filter operation. The final additive stages of beer processing require careful attention to sterility and regular checks on all materials used as well as flavour and foam stability of the final beer. In one brewery a sulphury oniony musty aroma was traced to poor lauter tun operation allowing husks to enter the copper. In another the fermentation was too rapid for the desired flavour owing to continuous circulation of pitched wort through a plate cooler for several hours while awaiting the next wort length. Other faults uncovered were mould growth under failed welds in a plate filter, inadequate regeneration of the carbon filter in the CO₂ system and the use of non food-quality rubber hoses. The lessons learned were put into practice systematically by going back to basics, questioning all operations, improving training and establishing a thorough audit system.
Keywords : beer brewing control evaluation process quality