From the enticing aroma of the turkey in the oven to the “whoosh’” of the flames as the brandy-soaked pudding comes alight, Christmas is a wonderful time for the senses. But have you ever considered the science behind our best-loved festive traditions? Here are seven of my food and flammable favourites:
Candle light, shining bright
Candle-lit carol services are part of Christmas for many people, as are the ones entwined in holly on the table. Traditionally beeswax was used but while it gives great flames, it is rather expensive. Nowadays the vast majority of candles are made of paraffin wax obtained as one of the products of oil refining. These waxes are hydrocarbons, molecules made of two different elements: carbon and hydrogen.
When you light a candle, wax is melted, and the molten wax gets drawn up the wick, which gives a larger area for the wax to evaporate. It is the gaseous wax that burns, forming carbon dioxide and water, and giving out energy, which is where the heat and light come from.
But not all the carbon atoms get turned into carbon dioxide at one go – it is carbon-rich soot particles glowing hot that give out the yellow light that characterises a candle flame.
Turkey time
Most people know that cooking involves chemistry, and where better to start than the Christmas Day turkey? The turkey meat you cook is muscle tissue, about 20% of which is protein (nearly all the rest is water), with a small but important amount of carbohydrate. If you “hang” the meat and allow it to age, enzyme catalysts naturally present in the muscle start to break down the proteins so that they lose their naturally rigid structure and the meat becomes more tender.