"The older it is, sourdough fanciers say, the better bread it makes; some Alaskan families have sour­ dough 50 years old." — Waverly Root and Richard de Rochemont, “Eating in America” 

Pioneer women carried leaven “mothers” across the plains to California, where sourdough bread has remained popular to this day. Sourdough got started in places where no yeast could be brought so had to be made naturally, capturing whatever wild yeasts were ini the air. Hops and beer helped, but plain flour and water ferment after 18 to 24 hours at nor­mal room temperature.