Homemade Bread Kvass

Method

1. 01

   Step 1: Dry the bread hard

   Spread the slices on a tray and dry them at 180°C for 12–15 minutes, until the edges are deep brown. That toasted crust gives kvass its colour and bready flavour, but avoid black patches — they taste burnt in the glass.

2. 02

   Step 2: Steep in boiling water

   Put the dried bread in a large pot, cover with boiling water and put a lid on. Leave for 8 hours, until the infusion is dark and completely cold.

3. 03

   Step 3: Strain it

   Strain through a few layers of muslin and resist squeezing the bread, which would leave the kvass cloudy. Stir in the sugar until it dissolves.

4. 04

   Step 4: Add the yeast

   Check that the liquid is barely warm, no hotter than 30°C, then whisk in the yeast. Hot liquid kills it outright and nothing will ferment.

5. 05

   Step 5: Let it ferment

   Cover with a cloth and leave at room temperature for 18–24 hours. It is ready when foam sits on the surface, fine bubbles rise as you tilt the pot, and the taste has gone from sweet to sharp.

6. 06

   Step 6: Bottle it

   Strain again and fill bottles, leaving 5 cm of headroom, and drop a few raisins into each one for extra fizz.

7. 07

   Step 7: Stop it in the fridge

   Give the bottles 4 more hours at room temperature, then move them to the fridge without fail — cold halts the fermentation. Open them slowly and over a sink; the pressure is real.