yeast / yeast cakes
A preparation used for raising dough for bread or cakes, and making it light and puffy; barm; ferment. — Webster, 1882
Barm; the foam, froth, or flower, of beer or other liquor in fermentation; any preparation used for raising dough for bread or cakes, and making it light and fluffy. — Webster, 1887
Raised Biscuit. Make a sponge of about a pint of milk and water, with a small piece of yeast-cake, or a penny’s worth of baker’s yeast at night; in the morning knead with a pint of milk, warmed, and half a cupful of butter and lard; knead very soft; let stand until night, then knead again; when light roll our; cut with a small glass; let stand for an hour in the pans; bake quickly. – The Redwood Gazette, March 1878
Commercial yeast used in bread-baking is a strain of Saccharomyces cerevisiae, an oval, microscopic, single cell living organism. When it metabolizes simple sugars, carbon dioxide and alcohol are released. These bubbles form pockets of gas in bread dough, causing it to rise.
There are wild yeasts, such as those that cause sour dough bread to rise, but it’s the commercial yeast cakes – also called compressed yeast – purchased from a store in the new town of De Smet that Caroline Ingalls is so excited to have in By the Shores of Silver Lake (see Chapter 29, “The Shanty on the Claim”). The Ingalls family had eaten some sort of risen bread in every Little House book prior to this chapter, yet it is the first one in which yeast is mentioned!
In the days before active dry yeast, Ma either relied on fresh cake yeast for her baking. If there had been a baker or brewer nearby, one could perhaps purchase a foamy yeast slurry as needed. It was carried home in a little pail kept for that purpose. There was also something called “yeast powder” widely advertised during the Little House years, but this wasn’t yeast at all; it was baking powder.
During the railroad blockade in The Long Winter, no yeast or baking powder (or flour!) is available in town, so Ma went back to using sour dough for leavening. It’s not until “Christmas in May” (see The Long Winter, Chapter 33) that yeast is once again available, and Ma is able to bake light bread.
Fresh yeast such as Ma used was sold in little moist cakes wrapped in paper, and it didn’t stay fresh long. Look for fresh yeast in the refrigerated section of your grocery store, but note that it is sometimes hard to find. In the early 20th century, the process of drying active yeast was discovered, allowing for the sale of dehydrated, living granules of yeast, which is what many people use in bread baking today. In order to know if any yeast is alive, meaning it will consume nourishment and give off the bubbles that cause bread to rise, the recipe amount required is “proofed,” or stirred into warm water, with a bit of sugar added for food. If the mixture gets frothy and bubbly, it can be used. In the composite photo below, the image at left shows both dry active yeast and some cake yeast. The glass jar contains about a half cup of warm water, to which the equivalent of a package of yeast has been added, plus about 1/4 teaspoon of sugar. Note the bubbles forming on the liquid in the center photo. The photo at rights is after an additional fifteen minutes had gone by, and the bubbles have risen to the top of the jar! Normally, you would add the mixture to your recipe well before this time; you want the yeast to start putting all those good bubbles to work in your bread, not start popping and be wasted.
yeast / yeast cakes (SSL 29; TLW 19, 33), see also bread