Vienna bread  Vienna bread is a type of bread that is produced from a process developed in Vienna, Austria, in the 19th century. The Vienna process used high milling of Hungarian grain, and cereal press-yeast for leavening. In the 19th century, for the first time, bread was made only from beer yeast and new dough rather than a sourdough starter. The first known example of this was the sweet-fermented Imperial "Kaiser-Semmel" roll of the Vienna bakery at the Paris International Exposition of 1867. These sweet-fermented rolls lacked the acid sourness typical of lactobacillus, and were said to be popular and in high demand. Prior to this time, bakers had been using old-dough leavens, and they had discovered that increasing the starter's rest intervals between refreshment promoted more yeast growth and less gas production due to overwhelming lactobacillus numbers. At some point bakers began to add brewer's yeast, or beer yeast or barm, to the refreshments which produced a whiter, sweeter-tasting bread. A shortage of beer yeast for making sweet-fermented breads developed when beer brewers slowly switched from top-fermenting to bottom-fermenting yeast (Saccharomyces pastorianus), and thus the Vienna Process was developed by 1846. In 1845 the Association of Vienna Bakers announced a contest for the production of a sweet-fermenting yeast and the prize was awarded in 1850 to . The Paris Exposition credited the Vienna Bakery in 1867 as the first in the world to use press-yeast. Three types of bakes were exhibited by the Viennese bakery at the exposition: the sweet-fermented Imperial rolls, wheat and rye or solely rye loaves, and a large variety of fancy breads and sweet cakes. The Imperial rolls were made with the finer grades of flour, milk and water in a 50:50 ratio, beer yeast, and salt. Other breads made with the same grades of flour claimed to include: Teacakes, which added butter and may have excluded water in favor of milk; Gipfel or Pinnacle cake, which used milk (no water) and lard; and Brioche, made with milk and sugar. Vienna yeast was propagated utilizing a mash of malted corn, barley, and rye. Horsford did not assert hops were used in the production of press yeast. After pitching a small amount of yeast into the cooled wort, and introducing some air, the propagated yeast floated to the surface.