Yes we can: the art of preserving home-grown fruit and veg

Nicolas Appert deserves to be a household name. After all, his solution to Napoleon’s food preservation crisis fills most households’ cupboards, and yet I still had to google him to put a name to the man.

In 1800, the French “armies marching on their stomachs” were dying as much from rotting food as from their human enemies. Appert was a chef who worked out the connection between heat sterilisation of food and vacuum sealing against deadly germs. He won 12,000 francs in Napoleon’s competition, thereby ensuring another 12 years of glory for the self-proclaimed emperor, until the “nation of shopkeepers” stopped him in his tracks at Waterloo. Wisely, Appert stuck to conquests in the business world; using his prize money, he started the canning industry.

Without him we may not have one of the world’s most satisfying comfort foods: beans on toast. Ironically, many of those shopkeepers got quite rich due to Napoleon’s innovative inventor.

The new year means something special to gardeners and allotment holders. Many of us will spend happy hours in the final week of the old year poring over seed catalogues and planning crop rotation, looking forward to the “grand stretch in the evenings” that denotes spring is in the offing, and picturing the pleasure of spotting the first seedling appear on our windowsills or in a seedbed.

As the Grow it Yourself movement has begun to flourish in Ireland, I'm not the only allotment holder to find myself with gluts of ever-prolific vegetables such as courgettes and artichokes. To reduce the risk of family and friends dreading yet another gift of veg-glut, we have begun to do home bottling, or "canning" as it's known in America. In this way, canned stews, ratatouille – or our favourite, chickpea and courgette curry – allow our home-grown produce to grace our table throughout the winter. For particularly appreciative friends, we may consider parting with a jar or two at Christmas.

I’m itching to get planting as soon as spring has sprung. The first few years that we had allotments, however, my springtime enthusiasm led to an autumnal overabundance and shameful waste, as too many things ripened at once. Some vegetables and fruit do not freeze well, and, despite giving away some produce, I felt there had to be another way of preserving what I had worked so hard to grow. Full self-sufficiency was never an aim, but I wanted to eat home-grown vegetables for more of the year, even out of season.

My husband, Shaun, is an excellent cook. Even after a hard day’s work, he likes to prepare a home-cooked meal rather than eat ready-meals or takeaways. I, however, am best left to growing the vegetables, as my culinary skills stop at baking with our children. So Shaun has taken to organising cooking weekends to stock up. Many families do something similar, cooking a week’s dinners in one go.

Now, with canning and pickling, we can cook 10 family-sized portions of each meal, although once you start along this path it’s a slippery slope until you’re wondering if your parents never told you that you were Amish, or that if you tell anyone you will be accused of being a tinfoil-hat-wearing nutcase stocking up for a zombie apocalypse.

Water bath versus high pressure

Canning at home is hardly heard of in Ireland, and many people I've told about it react with scepticism. But in France it's normal to buy home-produced pâté or fois gras at the weekly markets that so many of us like to frequent on our holidays. The process is quite simple. There are two methods, depending on what food is to be processed: the water bath and the high-pressure canner.

Use the water-bath method for fruits and vegetables with high acidity. This can be done on the stove top with any saucepan large enough. The idea is to preserve without the use of lots of sugar, salt or vinegar. Things get cooked, but their flavour shouldn’t be altered massively. In comparison to making jam or chutney, use jars with separate rubber seals, such as Kilner jars. The heating process results in a vacuum seal, which preserves the produce. Fruit and vegetables to be canned must be unbruised and just ripe. Depending on what is being preserved, simmer for the recommended time, which you can calculate using guides available online or in many cookery books. Once cool, store the jars away from light to keep their lovely colours.

Many people will consider this too much work, when many fruits can simply be frozen. If, however, you have a pear tree or French bean glut, the benefits of canning are evident. Water-bath canning can also be used for canning juices and tomatoes. It’s also helpful if your freezer is already full – as ours is – with the whole outdoor-reared pig we buy and my husband butchers every few months.

The second method uses a high- pressure canner. This enables the temperature to rise much higher than in a water bath, therefore allowing the preservation of low-acid foods including many vegetables and also meats.

To can using the high-pressure method, it’s necessary to invest in a high-pressure canner. An ordinary pressure cooker is not safe for this purpose, and wouldn’t be large enough anyway. We imported one from the US, as it proved impossible to source one closer to home. It was expensive enough, $100 on eBay, plus handling, but it’s invaluable to us.

As gardeners, it’s wonderful to be enjoying home-grown produce out of season, prolonging the joy of eating what we’ve produced ourselves.

The method for using the high pressure canner is very similar to the water bath: whole vegetables such as beetroot are processed raw, or meals such as chickpea curry should be partially cooked in advance, allowing the canning process to cook it further.

How to stop explosions

The pressure canner works on steam pressure, much like an ordinary pressure cooker does; you keep it at a particular pressure for a specified amount of time. As the equipment comes with an integrated pressure gauge, it allows you to know when it’s at pressure, and to stop explosions occurring.

Now winter is here, our attic storage shelves are resplendent with a colourful array of canned produce, as well as ordinary jams and chutneys. Ultimately, the advantage of canning over freezing is that it is much quicker to prepare a home-cooked meal on busy days. Just don’t use it if the rubber seal doesn’t make a popping noise on opening.

We all enjoyed preparing the ingredients for our family cook-ins. My husband was head chef. I helped prepare, and the children loved shelling peas and drawing labels. It has been a real family affair.

As the shelves slowly empty, I’m beginning to plan next year’s crop; perhaps more peas, perhaps fewer courgettes. I suppose my own personal chef should have some say.

Canning is a highly satisfying endeavour. While we still use the supermarket for some canned stuff (it's difficult to grow a pineapple here in Dublin), I now have even more appreciation for the humble baked bean. Nicholas Appert is my new hero. Zombie apocalypse? Bring it on.

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