Kyselo – Czech Sourdough Soup

Do you want to try an authentic Czech specialty? Try the sourdough soup with mushrooms and a generous portion of fried eggs! Czechs call this soup Kyselo. It is most often served in the northern regions of Bohemia, a mountainous area around Krkonoše (Giant Mountains).

What Is Kyselo Sourdough Soup?

Kyselo is a hearty soup made with a sourdough starter. Sourdough, or fermented flour, thickens the soup and adds a slightly sour taste. The soup includes dried porcini mushrooms and scrambled eggs with onions. A typical Czech spice, caraway seeds, gives even more flavor to the dish.

The Kyselo soup is dense and filling, served as a main course with potatoes or a slice of rye bread.

MY TIP: Try another famous Czech soup – sauerkraut soup, also known as "zelnacka". (it tastes fantastic!)

Ingredients

To make the Kyselo sourdough soup, you'll need:

• Sourdough starter; a fermented mixture of flour and water, most often used for baking sourdough bread. In the Czech Republic, we buy sourdough starter in bakeries or make it from scratch at home.
• Porcini mushrooms, dried
• Caraway seeds; a typical Czech spice. Use whole caraway, not crushed. Do not confuse caraway with cumin!
• Pork lard; to fry onion and eggs. If you don't have lard available, feel free to substitute it with vegetable oil (sunflower or Canola).
• Onion
• Eggs; we will fry the eggs with the onion and add the egg mixture to the soup at the end.
• Water; for the soup. This kyselo soup calls for plain water only, not broth.

For serving:

• Potatoes; boiled with skin on, peeled
• Butter; to pour over potatoes
• Chives; finely chopped chives are sprinkled over the potatoes

✅ You’ll find the exact amount of ingredients below in the recipe card, which you can also print out.

Instructions with Photos

THE DAY BEFORE:

a) Put the dried mushrooms in a saucepan and cover them with about two cups of water. Let them swell overnight.

b) Dissolve the sourdough starter in a cup of lukewarm water and leave it on the kitchen counter overnight. A mix prepared in this way will ensure that the soup is only slightly tart, not too sour.

c) If you want to serve peeled potatoes with the soup, cook the potatoes with the skin on. Count on about two smaller potatoes per serving.

Let's cook!

STEP 1: Bring the soaked mushrooms to a boil and simmer for 15 minutes over low heat. Do not pour off the mushroom broth!

STEP 2: Remove the mushrooms (still in the mushroom broth) from the stove, add the mixed sourdough starter, whisk it well. Pour in the water, salt the base and add the caraway seeds.

STEP 3: Bring the soup to a boil, turn the heat down to about half power and cook for 15-20 minutes. Do not forget to stir from time to time. The sourdough flour sits at the bottom of the pot, where it can burn.

STEP 4: Peel the onion and chop it finely. Heat the lard or oil in a frying pan and fry the onions in it until golden brown, stirring (photo 1). Crack the eggs into the pan with the onions, stir and fry them (photo 2).

STEP 5: Add the fried eggs to the finished soup, season with salt if necessary, and serve.

Serving

Czech Kyselo is a hearty and filling soup. For this reason, it is usually served as a main course.

The soup pairs well with a slice of fresh bread. However, peeled potatoes are also a good choice. These are placed in the middle of the soup plate. Pour a little melted butter over the potatoes and sprinkle them with chopped chives.

We then slice the potatoes with a spoon at our house during the meal. In other families, they serve the potatoes separately in a bowl, and the diners nibble on them with the soup.

Useful Tips

• Kyselo is a meatless soup; it does not include broth. It is cooked with plain water. If we close our eyes to the lard on which the onions and eggs are fried, you can easily describe this soup as "vegetarian."
• The sourdough starter, which is the main ingredient here, contains the flour. The flour thickens the soup as it cooks. It may seem too thick the next day if any soup is left over. In that case, add a little water to the soup while heating and stirring well.
• If you want a stronger flavor, season the soup with a little freshly ground black pepper at the end of cooking.

More Czech soups:

• Clear garlic soup (česnečka)
• Lentil soup (čočková polévka)
• Potato mushroom soup (bramboračka)

Recipe card