I love reading old cookbooks because the recipes are really interesting. When I grew up, my father tried sourdough starter but the breads, pancakes, and other final products never tasted right so he gave up. It wasn't till years later, we figured out the problem. He kept it in a metal container. You can't do that because it absorbs some of the metal and tastes horrible.
In some of the books, there are recipes for something called salt rising bread. I'd never heard of it and wondered how salt could cause bread to rise.
No one is sure where the name came from but it developed in the early 1800's when commercial yeast was not available and housewives had to make their own. To create the rising agent, they'd mix a mash of cornmeal and milk or potatoes and milk which produced a nice bubbly mixture. This leavened the bread.
Unfortunately, it was almost hit or miss back then, getting a reliable leavening agent so the trick was to keep it warm. It is thought the salt raised part came from the rock salt women warmed and piled around the starter to keep it warm and fermenting. It takes 12 to 18 hours to get it to this point.
Once its nice and bubbly, its time to add the remaining ingredients and progress as normal. Its said the final product is a dense - cheesy loaf.
If you'd like to try it yourself here is the recipe.
The sponge is made from 1 cup warm milk, 1/2 cup cornmeal, 1 tablespoon of sugar and 1 teaspoon of salt. Mix and set in a warm place until its bubbly and releasing gas. This step takes around 10 hours. Add in 2 cups of flour, 2 cups warm water, 2 tablespoon sugar, 3 tablespoon melted shortening. Mix and let set for 2.5 to 3 hours until its nice and bubbly.
Dissolve 1/2 teaspoon of baking soda in 1 tablespoon water before mixing with the sponge. Add in about 5.5 cups of flour. Knead, adding flour as needed, for about 10 minutes till smooth. Cut the dough into three parts, shape and place in baking pans. Let rise till doubled and bake at 350 till nicely golden brown.
Have a great time trying it.