Image adapted from: Antarctic Heritage Trust; with permission

A fruit cake from Scott’s 1910–13 Antarctic expedition has been found in Antarctica

Would you eat a 100-year-old fruit cake?

Christmas cake. Love it or hate it, it’s always around at this time of year. And it often lingers …

As with Christmas puddings, which are generally made months in advance then left to allow the flavours to diffuse and deepen, many people think that fruit cakes are improved by letting them age for a few months.

But there’s a bit of a difference between a few months and … 100 years. Conservators working in Cape Adare, Antarctica, recently found a tin containing a fruitcake that is thought to date back to the Terra Nova expedition of 1910–13. The cake is Huntley & Palmer’s brand, which is known to have been taken by Scott on his expeditions. Although its tin was a little rusty, apparently the cake itself looked to be in near-perfect condition—it ‘looked and smelt (almost) edible’.

So what’s going on in this collection of fruit, eggs and flour that enables fruit cakes to last so very long?

There are a few reasons foods go bad. Or spoil, go mouldy, turn rancid, putrefy, rot, decompose, go off, whatever you want to call it! Different foods go bad in different ways—proteins turn putrid and green, carbohydrates ferment, fats go rancid and sour.

mouldy beans — Different foods go bad in different ways—proteins turn putrid and green, carbohydrates ferment, fats go rancid and sour. Image adapted from: Leif K-Brooks; CC BY-SA 2.0

One of the leading culprits is the activity of microbes—microscopic organisms that can grow and multiply on and in food. Bacteria, yeasts and moulds can grow on the surface of food and, depending on the type of food and its structure and density, penetrate deep within the food (this is why it’s sometimes ok to just chop the mouldy bit off, say, a piece of hard cheese, but once one slice of bread shows some mould, it’s best to chuck the whole loaf).

Other factors are air (namely the oxygen) and moisture. These can provide more enticing habitats for the microbes, enhancing their growth. Oxygen can also directly cause spoilage, as it reacts with chemicals in the food to cause oxidation, or helps drive other chemical reactions involving enzymes within the food.

Our modern methods of food storage and preservation work to combat these processes: we refrigerate and freeze food to slow down the growth of bacteria, and we add chemicals to suppress the oxidation and enzyme-driven reactions within food. And we’ve been adding chemicals to preserve our food for a long time—salt, sugar, vinegar and alcohol are all age-old preservatives.

a jar of pickles — A combination of vinegar, salt and sugar are used to preserve vegetables as pickles. Image adapted from: Devlyn; CC BY-NC-ND 2.0

But back to the 100-year-old fruit cake.

Fruit cakes are a model example of food preservation methods. For starters, the fruits and nuts used to make them are dried, so moisture that would otherwise support the growth of microbes has already been removed. The addition of sugar also acts to suck up moisture. The other key addition is alcohol. Bakers often wrap the baked fruitcake in a liquor-soaked (usually brandy or rum) cloth, which helps prevent mould and yeast from growing on the surface. Which is best out of brandy or rum? That’s up to you and your tastebuds!

items on shelf — The project that unearthed Scott's (very) old fruticake collected several artefacts from the Cape Adare hut in Antarctica.

And of course, with Scott’s now-100-year-old cake, the other big factor is that Antarctica is very cold. This cake has essentially been sitting in the freezer for a century.

However, there was just one suggestion that the cake hadn’t entirely withstood the test of time—reports that the cake carried an ever so slightly rancid smell, suggesting that the fats in the cake might have gone bad.

The other question is what the cake will actually taste like after 100 years—while a few months, or even a couple of years is considered to enhance the flavours in a fruit cake, 100 might just be a decade or three too many. But there’s only one way to find out.