New technology is often driven by war. The internet originated via the military and so did the revolutionary technique of canning.
'An army marches on its stomach', said Napoleon, who offered 12 thousand francs to whoever could invent a new method of preserving food for long periods. Rising to this challenge, confectioner and chef Nicolas Appert spent 15 years inventing 'canning' or 'mise en boite'. At first food was preserved in glass jars. Around the same time in Britain, Peter Durand discovered a similar method, but used tin plated cans rather than breakable glass. As food became industrialised via factory processes, all canning evolved into food in tins. Canning is one of the most important inventions in the history of food, it's changed how we live. George Orwell declared: "I think it could plausibly be argued that changes of diet are more important than changes of dynasty or even of religion. The Great War, for instance, could never have happened if tinned food had not been invented."
Tinned food has become synonymous with culinary laziness and poor quality, the stuff of student meals and bachelor dinners (although the quality of French tinned goods such as petits pois and beans is excellent). To open and heat up a tin for supper is considered the equivalent of eating junk food. Most tinned food is safe, although we are warned to avoid dented tins. Recently, food technologist and writer Harold McGee wrote a fascinating article of aging tinned foods.
Clearly it's impossible for the home cook to reproduce the tin can at home but the original glass jar technique is both superior in flavour and fairly easy to do. Furthermore this captures the fresh taste of fruit and vegetables, picked straight from the garden or the allotment.
So Gloria Nicol and I did a workshop whereby we explained how to preserve food; firstly with water bath canning and secondly, with pressure canning. The latter is popular in the United States, and is often referred to as the 'canvolution'. The difference between the two techniques can be summed up in one word 'acidity'. What they have in common is that both methods preserve via a vaccum and heat treatment.
Water bath canning, more common here and on the continent, is useful for foods that already have high acidity, such as rhubarb. The equipment needed is easily found, either using the Le Parfait water bath or, a large deep saucepan.
Pressure canning is more technical, plus the equipment is harder to obtain in the UK. I imported my pressure canner from the States via Amazon. (Note: a pressure canner is similar to a pressure cooker but you must not pressure can in a pressure cooker). Pressure canning preserves low acidity foods, with a PH higher than 4.6. Even modern tomatoes are not considered sufficiently acidic, (the acidity having been bred out of them), one must add lemon juice or citric acid. Here, in this previous blog post, are some pointers for safe canning or 'bottling' as it is called here. I also, to avoid any errors that might lead to botulism, bought the USDA guide to canning. In the United States, with its large rural population, pressure canning is widespread therefore the cost of the jars is cheaper. Some of the jars, the quilted style Mason containers in glass, are very stylish and almost impossible to obtain here. In the UK we can buy Le Parfait, Weck and Kilner jars for pressure canning.
Canning is ecological, it preserves without the use of refrigeration and is ideal for gardeners who will have a 'glut' of produce, all at the same time. This way the gardener can use their produce throughout the year.
Gloria and I made a 'jar meal':
Cocktail in jars: rhubarb cordial with orange vodka and soda water
Salad in a bottle in a box
A canned bean soup served in a jar
Hand pies made from pickled walnuts, broad beans and blue cheese.
Sponge cakes with rhubarb preserves baked in antique French jars
Guests were sent home with lovely goodie bags including a jar lifter, a jar from Le Parfait, half dozen eggs from Gloria's chickens.
|Salad in a box|
|Cocktails in jars|
|Sponge cakes baked in French antique jam jars|
|MsMarmite (left) and Gloria Nicol (right)|