Dr Richard Evershed and his team from the School of Chemistry, Bristol University, have developed a technique to analyse pottery sherds - fragments of pots - some of which date back as far as the Bronze Age. Because the clay was not glazed, it acted like blotting paper and absorbed fats and waxes from whatever was put in the pot.
Dr Evershed and his researchers grind the sherds into a fine powder. His excuse for destroying archaeological remains is that "they are not treasures by any means. Archaeologists have hundreds and thousands of individual pot sherds - they're quite prepared to part with some of them."
He and his team combine two processes - gas chromatography and mass spectrometry, which separates out all the substances that have been absorbed by the clay and identifies what they are. The fats were typically from animals, although wax from leaves has also been discovered. The only plant identified so far turned out to be an ancient type of cabbage.
Combining Delia Smith with the History of Forensic Science, Dr Evershed's team has been cooking in the lab. Andrew Macdonald, an expert in recreating medieval pottery, threw some pots, using as models vessels that had been reconstructed from fragments. Dr Evershed cooked mutton and cabbage in these pots, then analysed them.
The pattern of fat deposition on the inside surface matched that found on some of the ancient pots, suggesting that they had been used as cooking vessels. Typically, the researchers found a ring of fat near the top, which would indicate that the meat had been boiled in water. If the meat had been roasted in a casserole-type dish, Dr Evershed reckons that fat would have been splashed across the whole of the inside of the pot.
Some of the ancient pots had been used for other purposes. A combination of animal fat and beeswax indicates a vessel was used for making candles. Beeswax was a valuable product, hence its dilution with the more readily available animal fat.
Pot sherds from a site at Isthmia on the Peloponnese peninsula in Greece contained large amounts of beeswax uncontaminated by any other fats. Archaeologists believe that the pots were hives, and the data gathered by Dr Evershed and his collaborator, Professor Virginia Anderson-Stojanovic, from Wilson College, Pennsylvania, help to confirm this. Reconstructions show bucket-shaped vessels with a large opening at the top and a tiny hole at the bottom.
"With a hole like that, they can't be cooking pots," Dr Evershed says; the hole was probably an entrance for the bees. The inside of these pots look as though a comb had been raked across the wet clay - presumably to give the bees some purchase when starting to build their honeycomb. Some of these ancient beehives are still used in Crete today.
Our ancestors made an effort to mend their favourite pots, using a black, tarlike adhesive that was obtained by heating birch bark. The major component of the glue, betulin, is the substance that makes the trunks look silvery- white.
What conclusion, I wonder, will researchers reach in thousands of years' time when they examine my family's cups - many of them stained with tea and repeatedly, painstakingly and messily glued together by my father with UHU.Reuse content