The invention of refrigeration was hailed as a major breakthrough in food preservation, especially for the fact that it became possible to keep food fresh long enough to transport it great distances. In an age before aeroplanes, it meant that sailors no longer got scurvy on long voyages. These days it just means that we stuff more carbon into the atmosphere trading food all over the world while forgetting old skills like how to preserve food by fermenting it.

Fermentation is the transformation of organic substances into simpler compounds by the action of enzymes produced by microorganisms such as moulds, yeasts or bacteria. It preserves food which would otherwise go off, such as vegetables, fruit and milk. Fermentation works by converting pruvate (from glucose) into ethanol and carbon dioxide (wine, beer, bread) or lactic acid (vegetables, milk products). The word ‘fermentation’ is derived from the Latin meaning ‘to boil’. Fermented beverages, such as beer, bubble and foam to the point where they look like they are boiling.

Human beings have been fermenting foods since the Neolithic. The first ferments were beer, wine and leavened bread (made primarily by yeasts) and cheeses (made by bacteria and moulds). These were soon followed by East Asian fermented foods, yoghurt and other fermented milk products, pickles, sauerkraut, vinegar (soured wine), butter and other alcoholic beverages. More recently fermentation has been used industrially to make vitamins B2 and B12, antibiotics and citric acid. Nutritional yeast and microalgae, such as spirulina and chlorella are also made by fermentation, as are many enzymes used in industrial and medical processes.

Fermentation is also the process by which living organisms, including humans, create energy without oxygen. In humans and higher animals, this occurs mostly in the muscles when energy is needed faster than aerobic processes can supply. It makes fight or flight possible.

The Lactobacillus family of bacteria ferment sugars into lactic acid. Think lactobacillus acidophilus used to make yoghurt. Another is lactobacillus plantarum, which can be purchased as a probiotic but is also found in fermented vegetables. It lives in our gastro-intestinal tract and in our mouths. It can synthesize amino acids and vitamins and help build immunities. It also supposedly eliminates sugar and carbohydrate cravings. Guess I mustn’t be eating enough.

Lactic acid preserves food by inhibiting the growth of harmful or putrefying bacteria. It also makes fermented food more easily digested. Here are some of the benefits of eating fermented foods:

• Fermentation neutralizes plant toxins, making vegetables more digestible.
• Fermentation of foods releases trapped vitamins and minerals from plant fibres
• Bacteria and yeasts themselves are replete with B vitamins
• Bacteria in the gut helps to stimulate peristalsis (faecal elimination), staving off constipation
• Friendly bacteria keep pathogens from gaining territory in our gut, i.e. they help keep us from getting sick
• A mother’s healthy microbial colony can prevent neonatal infections

Some fermented products, such as cheese, beer and wine, involve complex fermentation processes and lots of expensive equipment you can buy from many small businesses on the Internet. Kombucha (fermented tea) requires a SCOBY (symbiotic community of bacteria and yeast) that is kept alive by being allowed to ferment batch after batch of tea. Kefir grains and yoghurt bacteria also live to work and don’t live if there’s no work.

The easiest ferment to make is vegetables. Take some green beans or zucchini or any other favourite. Add some salt and leave for 10 minutes or so. Beat the veggies with one of those meat flatteners (or any other clubbing device) to release the juices. Stop if it feels too good. Put it all into an airtight container. Make sure the vegetables are covered in liquid; add water or whey if not. The vegetables must remain below the surface of the liquid; contact with oxygen interferes with the lactobacillus fermentation by introducing other not-so-beneficial bacteria. I cut up large chunks of carrot and sit them on top of my fermenting vegetables to keep them under the liquid.

Then you just leave the vegetables in their container at room temperature for a while, a week maybe or a few months. Open the lid daily so gases can escape, airtight containers have been known to burst from the carbon dioxide accumulating as the vegetables ferment. The longer you ferment, the more the flavour. So far I’ve only tried for a week. The carrot on top goes mouldy after a few days, but the vegetables underneath are fine. To stop the fermentation, you do need to put the jar in the fridge. Or you can eat the whole jar for lunch.