Here’s the recipe for the Authentic Polish Sour Rye, called Zakwas or Żur, a must-have ingredient to prepare the traditional soup Żurek!
You will need:
50 gr of wholemeal rye flour (1.76 oz);
250 ml of water, previously boiled and chilled to room temperature (8.8 oz);
1 sterile glass jar of 0.5 litre (17 fl oz) capacity, previously washed with boiling water.
Place rye flour and water in the jar, mix well with a wooden spoon.
Should you be lucky enough to have your own sourdough or some sourdough bread at home, you can either add a tablespoon of the sourdough or a small slice of bread in the mixture to speed up the process.
Close the jar with a piece of cloth, or leave the tap loose, and place it on the kitchen countertop, so that you can check its progress.
The mixture should start bubbling the day after. Its colour should always remain rather bright, never too brown, nor black.
If this happens, unfortunately the rye did not sour well and the whole content in the jar has to go into the bin.
Keep the jar at room temperature, within 20 to 25°C (68-77°F).
Your authentic Polish sour rye should be ready after 3 days, but you might have to wait up to 6 days to fully enjoy the real taste of Żur!
To know when the Żur is done, taste the mixture: if you feel a distinctive sourness on the tongue and the smell is slightly fermented, it is time to close the jar.
You may store it in the fridge, for a month.
Polish use this sour rye mixture exclusively to make the traditional soup Żurek, whose name evidently derives from the word Żur (sour).
The quantity obtained in this recipe is enough for circa 5 litres (1.3 US gallons) of soup.
If you need more, double or triple the doses.
Find the recipe for the Authentic Żurek soup here!