Żurek Starter (Zakwas)

Żurek starts with a sour rye ferment called zakwas. Put 4 tablespoons of wholemeal rye flour in a jar with a sliced garlic clove, a bay leaf, a few allspice berries and a crust of rye bread to speed things up. Pour in 500 ml of lukewarm boiled water, stir and cover with a cloth. Leave it somewhere warm and stir once a day. After four or five days it smells sour and slightly of yeast. Strain it and keep it in the fridge for up to two weeks. Shake it before adding it to the soup.