Fermented beet juice: six days on the counter and your borscht is ready
Zakwas is fermented beetroot juice, the base of a real Polish red borscht and, in winter, a drink people reach for like a tonic. It needs nothing beyond beetroot, salt and water — lactic acid bacteria are naturally present on the vegetables. Only two things need watching: the beets must stay permanently under the brine, because anything above it moulds, and the salt should be non-iodised and free of anti-caking agents — that is how Polish ferments have always been made, and the additives can cloud the brine.
Your own work in that: 35 min.
- Preparation 20 min
- Fermentation 8600 min
- Bottling 15 min
Step by step
0 / 6 doneMake the brine
Boil the water with the salt and cool it completely — 2 litres take about 2 hours to cool, so the brine is best made ahead. The ratio is 20 g of salt per litre — a two per cent brine, in which lactic acid bacteria thrive and spoilage bacteria do not. The brine must be cold: hot brine would kill everything meant to ferment.
Ingredients: 1500 g beetroot · 2000 ml water · 40 g coarse non-iodised salt · 6 cloves garlic · 3 pcs bay leaves · 6 pcs allspice berries · 1 pcs crust of rye bread
TipSea salt or rock salt, without iodine or anti-caking agents. Accurate weighing matters more than the type of salt, though — too weak a brine invites spoilage, too strong a brine stalls fermentation.
Peel and slice the beets
Peel the beetroot and cut it into thick slices — a centimetre, no thinner. Cut too fine, they release their sugar too fast, fermentation takes off violently and the ferment turns cloudy and over-sour.
Thick slices, a centimetre eachLayer into the jar
Into a large scalded jar (about 5 litres) pack the beetroot, layering it with the garlic, bay leaves and allspice. If you are using it, press a crust of rye bread on top — it supplies extra bacteria and gets fermentation going faster.
Layered with garlic and spicesCover with brine and weigh down
Pour over the cooled brine so the beets are completely submerged, and weigh them down with a small plate or a bag of water. Cover the jar with muslin or a loosely set lid. A piece of beet above the brine moulds quickly and can ruin the whole batch.
Ingredients: 1500 g beetroot · 2000 ml water · 40 g coarse non-iodised salt · 6 cloves garlic · 3 pcs bay leaves · 6 pcs allspice berries · 1 pcs crust of rye bread
Everything under brine, weighed downFerment for six days
Leave at room temperature (18–22 °C) for 5–7 days. Bubbles and foam appear after two days. Every other day, skim the foam with a clean spoon. Finished zakwas is deep ruby, clearly sour, and smells of pickles, not of decay.
TipA white film on the surface is usually kahm yeast — skim it off, the ferment is fine. Fuzzy, coloured mould means the whole batch must go.
Bubbles after two days, foam skimmed offStrain and bottle
Strain through a sieve into scalded bottles, filling them to the very top. Keep in the fridge for up to three months. Don't discard the beets: sliced, they go into borscht, salads or beetroot relish.
Bottles filled to the top, into the fridge
Before you start
Borscht from zakwas
Bring a vegetable and mushroom stock to the boil, season with garlic and marjoram, take it off the heat and only then add the zakwas. Boiling kills the live bacteria, and the borscht loses its ruby colour and fresh, sour taste.
As a drink
A small glass a day, cold. It contains live bacteria and is a traditional Polish winter tonic. The taste is assertive, salty and earthy — not everyone is convinced at first.
How long it keeps
Three months in the fridge in a tightly sealed bottle. It grows sourer and less sweet over time, which for borscht is an advantage.
Not sour enough
Leave it two more days on the counter and taste again. In a cool kitchen (below 18 °C) fermentation can take ten days — normal, and only patience is required.