The traditional pub cellar was a beautifully designed piece of engineering prior to the advent of mechanical refrigeration. Simple in design, with no moving parts, no noisy machinery, and no complicated controls, the cleverly placed holes in the walls at correct heights, and joined up by brickwork or slate-lined shafts, allowed the air to slowly pass through the cellar in a loop.
Thank you for reading this post, don't forget to subscribe!The Victorian and Edwardian engineers of the pub trade built excellent beer cellars. Long before the advent of mechanical refrigeration they worked out that the worst enemy of good beer is not warmth but fluctuation. So in a cellar at 10°C one night and 16°C the next, cask ale will fob, go flat or turn. But if the temperature is held constant at say 11°C to 13°C then the beer will look after itself.
These simple systems consisted of a low level intake (airbrick) on the north face of the building drawn in by the density of the air near the floor, and a high level extract (mushroom vent or brick shaft) allowing the warmer air to rise and leave the cellar. The vertical distance between the intake and extract created the required pressure difference for airflow, and the slow circulation of air was enough to keep the beer cellar “active” without creating unacceptable draughts.
But after the twentieth century many of these very effective systems were destroyed during refurbishments. A vent or shaft here and there was boarded over or rendered and the stable environment of the cellar turned into a sealed box which holds heat in much the same way that a thermos holds hot or cold liquids. There is a useful background explanation of how cellar temperature affects cask ale condition.
A large part of Gloucester’s pub stock is of old enough vintage to have been built with vaulted cellars of large proportions, made of the best Victorian sandstone with thick walls to moderate the external temperature. These cellars will be cool and of a constant temperature as long as the original ventilation has not been blocked in some refit, or the building converted to entirely different uses and the passive ventilation system logic has been lost. In these situations, the beer is cooled by mechanical means.
For Cellar Cooling Gloucester, visit https://www.acecc.co.uk/cellar-cooling/gloucester/.
The same principle is still true today – keep the temperature constant and allow the air to move slowly.