Lagering tanks

Maturing improves the taste and aroma of beer and the elimination of tannin, protein, and hop resins also has a beneficial effect. Some metabolic products of unpleasant taste are further converted or washed out by the carbon dioxide surplus. The time for lagering varies with different types of beer. For every type of beer there is an optimal lagering time, and longer lagering is usually detrimental to beer quality. The filled lagering tanks are subjected to the saturating pressure of carbon dioxide, usually 50—70 kPa (ca 0.5—0.7 atm), controlled by a safety valve. 

The beer from the primary fermentation is run slowly and without turbulence (thus ensuring no uptake of air) into lagering tanks which are usually cylindrical and horizontally disposed (Fig. 19.4). The traditional lagering... 

A typical cleaning sequence for plate heat-exchangers, enclosed fermenters, conditioning or lagering tanks, bright beer tanks and associated pipework is given below ... 

Under British conditions, lager primary fermentations are carried out in cylindroconical tanks at about 12 C (54°F) in some 4-7 days, the time being... 

Figure 20.2 Installation of dual-purpose outdoor (a) and indoor (b) cylindroconical vessels (CCVs) suitable for fermentation and lageiing. (1) Servicing platform. (2) Tank dome with fittings. (3) Insulation. (4) Cleaning in place inlet and spray ball. (5) Cooling zone for lagering. (6, 7) Cooling zones for fermentation. (8) Cone cooling zone. (9) Cone base. (10) Distribution panel with connection pipes. (11) Multi-way valve block.

For production of lagers, the fermentation process is carried out at 7°C to 15°C for 8 to 10 d, and for Pilsners at approximately 20°C for 3 to 5 d. Lagers are almost always fermented with bottom yeast, whereas Pilsners are always fermented with top yeast. Most beers are kept in closed tanks at a temperature of 0°C for 4-6 additional... 

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