Zakwasie

Zakwasie refers to the fermentation process and the resulting sourdough starter used in Polish cuisine. The term comes from zakwas, the Polish word for a souring culture. In practice, zakwas is a mixture of rye flour and water that, through lactic acid bacteria, develops a tart, acidic liquid used to flavor soups and as a base for bread dough.

Preparation typically involves combining rye flour with water in a clean, nonreactive container, sometimes with a small amount of rye crumbs. The mixture is covered with a cloth to allow airflow and left at room temperature for about three to five days, with daily stirring. The liquid becomes cloudy and acquires a sour aroma as fermentation proceeds. After fermentation, the liquid can be strained off for use in soups, while the remaining solids may be saved to refresh the starter for future batches.

Use of zakwasie includes adding the starter liquid to soups to provide acidity and depth, most notably żurek (sour rye soup) and barszcz (beet soup). It can also serve as a leavening agent for certain rye breads, contributing distinctive tang and aroma.

Storage and maintenance: zakwas can be kept refrigerated for up to one to two weeks and frozen for longer storage. To maintain a living starter, it is periodically fed with fresh rye flour and water.

Safety and quality: use clean utensils and containers to avoid contamination. Discard zakwas that shows mold, an off smell, or signs of spoilage. Properly prepared zakwas should smell pleasantly sour, not rotten.