How it works
The lactic bacteria naturally present on vegetables turn their sugars into lactic acid when they are deprived of air. Salt slows down unwanted microbes while the lactic bacteria take over; the acidity they produce then preserves the vegetables.
Never sterilize a lacto-fermented jar: heat would kill the bacteria that make the preserve.
What you need
- Very clean jars, ideally rubber-seal jars, which let the fermentation gas escape.
- Salt without additives (no anti-caking agent), such as coarse sea salt.
- Unchlorinated water: filtered water, spring water, or tap water left to stand for a few hours.
- Something to keep the vegetables under the liquid: a small glass weight, a cabbage leaf or a small jar.
How much salt?
In brine — whole or sliced vegetables
Carrots, green beans, cauliflower, radishes, gherkins: cover them with a brine of 30 g of salt per litre of water.
Dry salting — grated or shredded vegetables
Cabbage for sauerkraut, grated carrots or beetroot: count 15 to 20 g of salt per kilo of vegetables, and knead them until they release enough juice to be covered.
Step by step
- Wash the vegetables without peeling them too much and cut them as you like.
- Pack them tightly in the jar.
- Cover with brine (or with their own juice), leaving 2 to 3 cm of space under the lid.
- Place the weight so that nothing sticks out of the liquid, then close the jar.
- Leave the jar at room temperature (18 to 22 °C), away from light, for at least 5 to 7 days: bubbles show that fermentation has started.
- Then move it to a cool place — cellar or fridge — and wait 3 to 4 weeks before tasting; 4 to 6 weeks for sauerkraut.
Normal signs
- Bubbles, and brine that overflows a little when the gas escapes.
- A brine that turns cloudy and a white deposit at the bottom of the jar.
- A pleasant sour smell.
- A flat white film on the surface of the brine: these are harmless yeasts, simply remove it.
When to throw the jar away
Fuzzy or coloured mould on the vegetables, a putrid smell, or vegetables that have become slimy and soft: the fermentation has gone wrong, throw the jar away without tasting it.
Storage
Kept cool, below 15 °C, lacto-fermented vegetables keep for several months and keep getting more sour. Once opened, store the jar in the fridge and always take the vegetables out with a clean utensil.
