Bread Kvass
A homemade rye-bread ferment — mildly sour, faintly sweet and naturally fizzy, the drink that cooled Ukrainian summers long before refrigerators existed.
About this dish
Kvass predates written Slavic history: early chronicles mention it alongside mead and beer as an everyday drink rather than a festive one, because it was made from whatever was already in the house — stale bread, water and sugar. Rye bread, dried until the crust turns nearly black, is what gives the water both its colour and its faintly bitter edge, the thing that separates real bread kvass from a sweet soda imitation. Wild fermentation once relied entirely on the yeasts already living in the bread and the kitchen air, and the handful of raisins dropped into each bottle is the old, equipment-free trick for coaxing in the last bit of fizz.
- Vegan
- Lactose-free
- Contains gluten because of Stale rye bread
Ingredients
- 400gStale rye bread
- 3lWater
- 150gCaster sugar
- 5gDry yeast
- 20gRaisins
- 4sprigsFresh mint (optional)
Instructions
Slice the rye bread and dry it in the oven at 180°C for 20 minutes, until the crust is dark brown, almost black, without burning.
20 minTip: The darker the toast, the darker and richer the kvass — it is the toasted crust, not the raw crumb, that gives kvass its characteristic nutty edge.
Put the toasted bread in a large pot or jar, pour over the boiling water, cover and let it steep for 5–6 hours or overnight, until it has cooled to room temperature.
5 minTip: It has to be boiling water: the heat pulls the starches and sugars out of the bread immediately, which fermentation later turns into the drink's gentle tang and bubbles.
Strain the infusion through muslin, pressing the bread to extract it fully, dissolve the sugar and yeast into the warm liquid, cover with a cloth and leave at room temperature for 8–10 hours.
0 minTip: A cloth, not a lid: the fermentation needs air, and a sealed container either stalls the process or, worse, builds up enough pressure to burst.
Once a light foam forms on top and the kvass tastes pleasantly sour-sweet, strain it again, bottle it with a few raisins in each bottle, and seal tightly.
0 minTip: Raisins are the traditional trigger for a second, quieter fermentation: the sugar on their skins sets off one last burst of activity right inside the sealed bottle, which is where the fizz comes from.
Refrigerate the bottles for at least a day before serving, and pour it very cold, with a sprig of fresh mint if you like.
0 minTip: Cold slows fermentation rather than stopping it, so a chilled bottle keeps developing flavour for several more days — it is worth tasting one a day or two after the first.