What is a Sourdough Starter? "A sourdough starter is a wild yeast living in
a batter of flour and liquid. Yeasts are microscopic fungi related
distantly to mushrooms. There are many varieties of these tiny organisms
around us everywhere. Wild yeasts are rugged individualists which can
withstand the most extreme of circumstances. Some will make delicious
loaves of bread; others will create yogurt and cheese out of milk; still
others will turn the juices of grains and fruit into beer and wine."
"Active dry yeast, the kind we can buy in packets at our grocer's, is a
domesticated descendant of these wild relatives, one which has been grown
for flavor, speed of growth and predictability. But domestic yeasts are
much more fragile and can't be grown at home without eventually reverting
to their original wild state."
"If you can imagine a world without any packets of active dry yeast, you
can imagine how important your sourdough starter would be to you. Without
it, you would be doomed to some pretty awful eating. It is no wonder that
sourdough starters were treasured, fought over, and carried to all ends of
the earth. To the early prospectors, it was such a valued possession
(almost more than the gold they were seeking), that they slept with it on
frigid winter nights to keep it from freezing. (Ironically, freezing won't
kill a sourdough starter although too much heat will.)"
Fermentation (or the Microscopic Magic of Yeast): "As we mentioned above,
yeast is a microscopic fungus. As it feeds on the natural sugars in grain,
it multiplies and gives off carbon dioxide (just as we do when we breathe).
This invisible activity of yeast is called fermentation. When you make
bread with wheat, by kneading the long elastic strands of wheat protein
(called gluten) into an elastic mesh, you create traps for these carbon
dioxide bubbles causing the dough to expand as if it contained a million
tiny balloons."
