A wonderful massively interesting trade card for Warner’s Safe Yeast circa 1885-1890. To this day, companies sell products by creating fear and then offering a solution. This ad falls squarely in the fear mongering tradition. It would not have seemed so absurd to people in its own time.
For hundreds of years dense bread was thought to be indigestible. Its indigestibility had been mentioned in health manuals going back to the 1500s. The poor were often afflicted with gastrointestinal illnesses and for various reasons, their breads were also often dense. In the 1880s the germ theory of disease was still reasonably recent and so the bad water and unsanitary conditions that were in fact responsible for the gastrointestinal ill health of the poor was not yet fully appreciated by popular culture. Thus, in folk culture, dense bread made you sick. That is the back story. Commercial yeast reliably yields a lighter bread, one with a more open crumb, than breads leavened with homemade yeasts or sourdough cultures. Given an unscientific understanding of stomach cramps well made yeasted bread could be imagined to prevent them.
But there was a rub. Commercial yeast cost money; many American cookbooks included recipes for home yeast cultures, and had since the early decades of the century. Homemade yeast was a well established part of American home baking, which was itself at this point in our culinary history an established part of the home economy. Waste not want not. Why buy yeast if you could make your own? A simple answer to that would be that yeast is quasi-medicinal in its effects. Who would turn their backs on the health of their family? Affluent households had long been buying commercial yeast by the 1880s. This ad is not addressed to them.
Lest you think I exaggerate the nineteenth-century fear of heavy bread. Here is Catherine Beecher on heavy bread published in her 1848 cookbook, Miss Beecher’s Domestic Receipt Book.
Perhaps it may be thought that all this is a great drudgery, but it is worse drudgery to have sickly children, and a peevish husband, made so by having all the nerves of their stomachs rasped with sour, or heavy bread.
Similar sentiments were expressed into the early twentieth century, if with less animus toward the put upon baker.