Before refrigeration, before canning, before most of what we now think of as food preservation — there was fermentation. The process requires no heat, no specialist equipment, and very little skill. What it requires is patience and a small amount of trust in the invisible biology that makes it work.
The Basic Science
Lacto-fermentation works through naturally occurring lactobacillus bacteria, present on the surface of most vegetables. In a salt brine, these bacteria convert the sugars in the vegetables into lactic acid. That acid then preserves the food and creates the characteristic sour, complex flavour of properly fermented vegetables. Salt keeps harmful bacteria at bay while the beneficial ones do their work.
Starting With Sauerkraut
Sauerkraut is the ideal first project. Shred half a cabbage finely — about 700g. Weigh it, then add 1.5% of that weight in fine sea salt (roughly 10-11g). Massage the salt into the cabbage with your hands for five to ten minutes until it releases its liquid. Pack tightly into a clean 1-litre jar, pressing down firmly so the brine rises above the cabbage. The cabbage must stay submerged — use a small zip-lock bag filled with brine as a weight.
Cover loosely and leave at room temperature. After two to three days you’ll see bubbles — that’s fermentation beginning. After one week, taste it. After two, it will be more sour. After three to four weeks, it’s ready to move to the fridge, where it will keep for months.
What to Ferment Through the Seasons
Spring: wild garlic capers, ramp leaves, radishes. Summer: green beans, cucumber, courgette, cherry tomatoes. Autumn: green tomatoes (before the first frost), cabbage, carrots, beetroot. Winter: the preservation of summer’s abundance becomes the pantry staple for cold months — open a jar of summer-fermented beans in January and the season comes back to you.
The appeal of fermentation isn’t just practical. It builds a relationship with time that most modern cooking doesn’t allow. You make something, you wait, and then — days or weeks later — it is different, and better, than what you started with.