The following letter to The London Review of Books was in response to an article by the classicist Mary Beard (@wmarybeard), in which she described the ‘well-known conundrum’ of big, porous jars set into Ancient Roman bar counters. In my letter, I hypothesise a possible solution to the conundrum. I give a fuller account of my hypothesis, including a photograph I took in Pompeii of such jars, on the Friends of Charles Darwin blog. A slightly edited version of my letter appeared in the 24th January 2013 edition of the LRB.
Mary Beard describes the conundrum of the big storage jars set into the shop counters of Pompeii and Herculaneum: they were unglazed, which would surely make them unsuitable for the storage of food or drink (LRB, 3 January). In some hot countries, such as Spain and India, porous pots are still used to cool water. In a process similar to human sweating, water stored in the pots slowly seeps to the surface and evaporates, thereby cooling the pot and the water that remains inside. In a more modern, African take on this old idea, glazed food-storage pots are placed in wet sand inside larger porous pots to make solar-powered ‘pot-in-pot refrigerators’. Perhaps Mary Beard’s enigmatic jars were the Roman equivalent of wine chillers.
Hebden Bridge, West Yorkshire