Carl Griffith's sourdough starter

Carl Griffith's sourdough starter, also known as the Oregon Trail Sourdough or Carl's starter, is a sourdough culture, a colony of wild yeast and bacteria cultivated in a mixture of flour and water for use as leavening.^[1] Carl's starter has a long history, dating back at least to 1847, when it was carried along the Oregon Trail by settlers from Missouri to Oregon. It was then passed down as an heirloom within the family of Carl Griffith, who shared it via Usenet in the 1990s.^[1] Since 2000, it has been maintained and shared by a dedicated historical preservation society; its volunteers keep the starter alive, feeding the organisms flour and water, and mail free samples worldwide on request for use by bakers in seeding their own cultures.^[2]

As with any other sourdough starter, the yeasts in Carl's starter generate carbon dioxide by fermentation when added to bread dough, causing it to rise.^[1] Bacteria of the genus Lactobacillus produce lactic acid, giving the bread a sour flavor.^[2] Carl's starter is especially robust, quick-rising, and tolerant of mistreatment,^[3] producing a consistent, reliable rise and good flavor.^[1]