How to Make Yeast (1860)

"Boil one pound of good flour, quarter of a pound of brown sugar, and a little salt in two gallons of water, for one hour. 

"When milk-warm, bottle it and cork it close. It will be ready to use in twenty-four hours. One pint of this yeast will make eighteen pounds of bread."

(Origin - "Civil War Recipes - Receipts from the Pages of Godey's Lady's Book" compiled and edited by Lily May Spaulding and John Spaulding.)