'Preserving vegetables for months, using neither heat, cold nor preservatives, yet retaining the original freshness and nutritional value of these vegetables - this is the 'miracle' of lactic fermentation.' Quote from Preserving Food, Deborah Madison
It sounds very technical but it's what you do to cabbages to make them into sauerkraut or Korean 'kimchi'. It is a very old method of preserving which was in use before heat sterilisation was discovered. In the process, lactic acid fermenting organisms develop spontaneously converting the sugars in the vegetables to lactic acid. This increase in acidity kills organisms that would normally cause the vegetables to spoil. It is the lactic acid and simple alcohols produced by the organisms that give lactofermented food its unique tangy taste.
The health benefits of lacto fermented foods are many. They are rich in vitamin C; the lactic acid is a great aid to digestion; and they keep the intestinal tract very healthy. It's best not to eat too many at once but are great with other foods.
It is a practice still widely used in Bulgaria. Every October and November, women gather their cabbages for lacto fermentation. Since being here I have learned two methods for making 'kiselo zele' (lit. sour cabbages) from my neighbours, both of which work equally well. This is Baba Hristana's method:
Remove outside leaves.
Cut a cross deep into the heart of each cabbage.
Pour salt into it and stack the cabbages in a plastic barrel. There should be a tap fitted to the barrel.
Leave overnight. Next day, fill the barrel with water until it covers the cabbages. Add a couple of beetroot and a lemon cut into 4 pieces each.
Put a weight on top of the cabbages so that they remain submerged.
Every 2-3 days strain off all the liquid and pour it back into the barrel. Do this over a period of about 9 days.
Leave for 3 weeks and then your cabbages are ready to use.
There are some delicious traditional recipes using the leaves which I'll post later.