Preserve your raw vegetables for months with this lacto-fermentation technique.
This tutorial has been created in collaboration with Claire Yobé, a lacto-fermentation instructor with over thirty years of experience in the field.
The aim is to easily preserve surplus vegetables for long-term storage, whether from your vegetable patch (in Summer for example), or because you have bought more vegetables than you needed.
Key facts on food wastage:
What is lacto-fermentation, or lactic acid fermentation?
Lacto-fermentation is the conversion of sugars into lactic acid by lactic acid bacteria (naturally present specific microorganisms).
This method of fermentation has been used for centuries to preserve milk (e.g yoghurt), vegetables (e.g sauerkraut), meat (e.g. cured sausage) and even fish (e.g fish sauce).
How is it possible to preserve vegetables by means of lactic acid fermentation?
Vegetables carry microorganisms on their surfaces (microscopic fungi, bacteria) which, when left in the open air, cause them to rot. The absence of air (anaerobic conditions) and a small quantity of salt to inhibit other bacteria, encourages the lactic acid bacteria to grow: this is the start of the lacto-fermentation process.
These bacteria grow by feeding off the sugars present in the food, and converting them into lactic acid. The amount of lactic acid gradually increases, and the vegetable juice becomes increasingly acidic.
This acidity neutralises the rotting process. When the medium is acidic enough (approx. pH 4), the lactic acid bacteria are also inhibited. The product becomes stable, which allows for long term storage of up to several months and sometimes even years.
What kind of vegetables can be preserved by lacto-fermentation?
Nearly all vegetables which are eaten raw can be preserved this way. (E.g cabbage, cucumber, carrots, beetroot, etc...)
What are the nutritional and health benefits of lacto-fermented vegetables?
1) They aid digestion and nutrient absorption.
Enzymes in lactic acid bacteria "pre-digest" vegtables, which helps the digestion process as well as the absorption of nutrients and minerals by the body.
2) They are a source of vitamins.
Lacto-fermented vegetables have the same amount of vitamins, and sometimes more, as raw vegetables.
3) They help the intestines and immune system function properly.
Lactic acid bacteria are "pro-biotics" for the gut flora which play an important role as barriers for the immune system.
How can we consume lacto-fermented vegetables?
Lacto-fermented vegetables can be consumed frequently, on a daily basis even, for example as a side dish.
Eating a lot in one go can cause stomach pains due to its elevated acidity levels.
They should be part of a varied and balanced diet.
Are there any risks involved with lacto-fermentation?
Contrary to preservation by means of heat (e.g sterilisation) or freezing, which can in turn cause the growth of, for example, the toxin botulinum, lacto-fermentation is a very safe method.
The acidity of the medium prevents the growth of pathogens.
Nevertheless, if in doubt and bad odours or peculiar colours appear, throw the preserve away.
Note: Pressing down allows for the salt to penetrate the vegetables so as to encourage the extraction of juices and get rid of air
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This English translation has been possible thanks to the PerMondo project: Free translation of website and documents for non-profit organisations. A project managed by Mondo Agit. Translator: Annie Eve