Polish Sour Rye Soup (Zurek Polski) - cooking recipe

Ingredients

For the kwas
75 g wholemeal rye flour
600 ml boiled, cooled water
1/4 clove garlic
For the soup
1 1/4 liters vegetable stock (or beef/chicken bones)
100 g bacon
100 g onions
1 can mushroom
400 ml kwas
300 ml sour cream
5 medium potatoes, cooked and diced
100 g smoked sausage, diced

Preparation

Rinse out an earthenware jar or any non-aluminium container with boiling water.
(Note: the aluminium would react with the acidity of the kwas).
Put the flour in the jar and mix to a liquid paste with a little of water.
Leave the mixture to settle for a few minutes, and then pour on the remaining boiled water.
Chop the garlic and add.
Cover the top of the jar with muslin or pierced cling film and leave in a warm place for 4 to 5 days to ferment.
Strain and use as required.
If stored in an airtight container, it will keep for a few weeks.
Heat the stock.
Chop bacon and onion and add to stock.
Simmer for 10 minutes.
Add mushrooms, kwas, cream and garlic.
Season with salt and pepper.
Allow to simmer for 20 minutes and then add potatoes and sausage.
Bring to boil.