Consumption has to a great extent switched from rye bread to wheat bread. Shchi is traditionally eaten with rye bread. It is usually served with rye bread or crackers. Modern bread variations might include wheat, pumpernickel, sour dough or rye bread. Some wheat allergies allow the use of rye bread as a substitute. Rye bread contains ferulic acid dehydrodimers. Meatballs, pea soup and rye bread are examples of such staples. The forced workers only had two pieces of rye bread to eat daily. Schwartz's signature dish is a smoked meat sandwich served on rye bread with yellow mustard. Pure rye bread contains only rye flour, without any wheat. It is often served on rye bread with horseradish-style mustard. Black rye bread () accompanies almost every savory food in Estonia. Caraway is used as a spice in breads, especially rye bread. The stew is typically dished up with rye bread or boiled potatoes. Pickled herring is served as an hors-d'oeuvre or on rye bread as a lunch buffet.