- 3 slices stale sourdough/rye bread

- 100g sugar/honey/maple syrup

- 2L boiling water

- 1 tbsp sourdough starter

1. Toast the sourdough until almost black, this will give it a nice rich malty flavour.

2. Place the toast in a 3L jar with the sugar and the boiled water. Mix well until the sugar dissolves.

3. Allow the mix to cool to room temperature, then add the sourdough starter and mix well.

4. Cover the jar with a cloth and leave at room temperature for 3 days, stirring every day.

5. After the third day, strain through muslin or cheesecloth, then into a bottle.

6. Seal the bottle and leave it at room temperature for a further 2-3 days. The longer you leave it the more carbonated it will become.

7. It's ready to drink, but always nicer chilled, so store it in the fridge.