Sour rye soup is a type of soup that has a tangy and sour taste. It is made from rye flour, which is made from a type of grain called rye. Rye is similar to wheat, but it has a stronger flavor and is often used for making bread.
To make sour rye soup, the rye flour is mixed with water and left to ferment for a few days. This fermentation process is when tiny little living things called bacteria and yeast make the soup sour! They eat the sugars found in the rye flour and turn them into acids, which make the soup taste sour.
After fermenting, the rye flour mixture is cooked with vegetables, such as carrots, celery, and onions, and sometimes with bits of meat or sausage. The soup is then served with a garnish, like fresh dill or sour cream.
So, in a nutshell, sour rye soup is a soup made from rye flour, which is fermented to make it sour, and then cooked with vegetables and sometimes meat or sausage to make a delicious and tangy soup.