More on the art of preserving as expounded by Oded Schwartz in his book of that name. Whereas in the past, seasonal gluts of fruit, vegetables, fish and meat were preserved to ensure a year-round supply, nowadays home-made preserves are a luxury and a thoughtful gift, requiring little more than time. A stroll through a park or any lane on the outskirts of a city should provide a couple of handfuls of blackberries and elderberries, enough for a jar or two of jewel-coloured hedgerow jelly, which may be better appreciated as gifts than a box of chocolates or a bottle of wine. The earliest methods of preserving were probably sun- and wind-drying, which are still widely practised today, from wind-dried cod in Iceland, (exported to Nigeria) to sundried mangos in more tropical climates. (And surely they haven't given up on roof-dried fish in Donegal?) The preservative quality of salt was exploited by early man. Schwartz points out that the first biblically recorded war was fought over the rights to control salt pans (Genesis 14:10); and that in ancient Egypt, salt, vinegar and honey were used in the process of mummification. Sugar, seemingly, was a latecomer as a preserving agent. It was unknown to the Hebrews and ancient Egyptians, and receives no mention in early Greek or Roman writings. Sugar was brought to Europe in the 12th century by Arab merchants and returning Crusaders, but became an essential ingredient only in the 16th century when it was introduced to Europe from the West Indies. Schwartz cites vinegar is the third essential preserving ingredient, working by creating an acidic environment in which contaminating bacteria cannot thrive.
The fourth method of preserving food is to exclude air, traditionally by using honey or oil, though the principle applies nowadays to bottling, canning and vacuum-packing. The one method not mentioned by Schwartz is the old Irish habit of burying butter in the bog. Effective, certainly, though hardly flavour-enhancing. How many years did it remain edible in its casks? (Preserving: by Oded Schwartz, Dorling Kindersley 1996.)