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Cold Conditioning
On arrival at the Robinson’s Unicorn packaging Centre the beer is pumped through a chiller to a cold conditioning tank. The chiller works on the same principle as the wort cooler at the brewing stage but brings the temperature of the beer right down to 0°c. The beer is held at this temperature for a minimum of 10 days.
During this period of cold conditioning proteins and tannins such as those mentioned at the kettle boiling and wort separation, precipitate out of solution and form a strong haze. The removal of potential haze is further encouraged by the addition of a proteolytic enzyme derive from the papain plant. This enzyme selectively breaks down certain proteins thereby preventing them from ever coming out of solution and forming a haze.
This is quite a critical process, however, since protein removal can cause head retention problems when the beer is poured. Thus the enzyme used must be very selective about which proteins it attacks leaving untouched the proteins which form the head on beer. Of course head retention is less important in some parts of the UK than others, but by and large a good head that clings to the glass while being drunk is a desirable property in most parts of the world.
{Image of beer with head and image of cling.}
Although this period of cold conditioning is fairly simple and straight forward it’s importance cannot be exaggerated. If the beer is not held at a low enough temperature for a sufficient period of time some of the protein and tannins will remain in solution in the beer only to precipitate out later in bottle after a period of time or when it is chilled in a refrigerator, causing an undesirable haze.
While the beer is in this tank various physical checks are carried out against predetermined specifications of colour, abv, bitterness, CO2, OG and PG.
