Man’s bread making processes drastically changed during the 19th century when baker’s yeast was introduced. Different civilizations throughout history found that through the control of time, temperature, moisture, and oxygen they could control how bread turned out. What they may not have known is that they were controlling which microbes flourished and which didn’t. We see this clearly with alcohol fermentation which seams to have always gone hand in hand with bread making. By controlling these factors brewers are able to manipulate microbes to produce alcohol rather than vinegar through fermentation. By feeding grain and water often with a natural leaven, bakers promote yeast production which in turn produces carbon dioxide to give the baker light and airy breads.
In 1780, Dutch distillers began selling yeast commercially. This process known as the Dutch process spread to Germany around 1800 and yeast was sold in the form of cream. In 1825, the yeast manufacturer Tebbenhof devised a way to compress yeast into cakes while extracting moisture.In 1867 Reiminghaus developed the filter press which improved the industrial manufacture of baker’s yeast. This new process became known as the Viennese process and soon spread throughout the French market. These yeast cakes are still used today throughout Europe. I remember learning to make bread in the early 90’s in Finland with compressed yeast cakes that I had purchased at the local market.
Charles Fleischmann was an immigrant from Europe. Trained as a young boy in a distillery he learned all about a by-product of distilling, yeast. He was familiar with the new process of making breads with baker’s yeast and the fine breads of Europe. America at that time was still using the old fashioned methods of “salt rising bread” where natural leavened breads were placed in a barrel of salt which would retain the heat of the day so the dough could rise or proof over night. America was a new frontier not exposed to the new yeast of Europe. After several years of trying to convince Americans to switch from their old ways to the new yeast, Charles Fleischmann and his partner James Gaff presented their yeast in 1876 at the Centennial Exposition (world’s fair) in Philadelphia where they demonstrated the leavening power of their yeast, baked bread & pastries in their Vienna model bakery and served them to guests. The fair attracted 10 million visitors and catapulted Fleischmann’s compressed yeast into fame. Fleischmann cornered the market in America and ran adds such as “Everybody knows that Fleischmann & Co’s compressed yeast makes the best bread.”
Compressed yeast became the mainstay of baking until Fleishchmann again revolutionized baking by developing Active Dry Yeast during the onset of World War II. This new yeast didn’t need refrigeration and just needed warm water to activate, allowing soldiers to eat home-baked bread.
In 1984 Fleischmann patented a new process for isolating its desired strains of yeast in its trademarked rapid rise yeast where rising time was decreased by 50%. Today we still see compressed yeast cakes used in Europe. If you go to the grocery store in the U.S. you will find mostly Active Dry Yeast in various brands along with some of fleishmann’s Rapid Rise Yeast.
In my opinion, the isolation of preferential yeast strains isn’t inherently harmful to humans. However, these processes are essentially adding more baker’s yeast to breads to get a much more rapid rise. By using yeast in such large amounts, the yeast do not have time to break down the grains along with the fact that very few if any lactobacilli are present. Consuming too much of anything can be harmful. Some people have even developed antibodies to baker’s yeast which creates it’s own health challenges with consuming breads. The biggest problem with using baker’s yeast is man has not let nature work as it normally does allowing many forms of yeast and many forms of lactabacilli bacteria to live and grow together harmoniously. We have upset this yeast and bacteria balance that nature has so well developed and which providently detoxifies grains for human health and enjoyment.