What makes "sourdough" bread different from other breads such as white bread?

Question

What makes "sourdough" bread different from other breads such as white bread?

Answer 1

White bread uses a known strain of yeast to produce carbon dioxide to leaven the bread.

Store bought sourdough uses yeast (could be a different strain from the white bread yest) and a bacteria.  The yeast produces carbon dioxide and the bacteria produces the sour flavor.

Traditional sourdough bread was made with a wild yeast starter.

What happens is yeast and bacteria (some form of lactobacillus) feed on the same floury goop and live symbiotically.  

The yeast produces carbon dioxide and the bacteria produces acids (hence the sour taste) which kills off any bad bacteria.

Answer 2

It's the Sourdough starter that is the big difference. It's a fermented additive that gives it that wonderful tangy flavor. As much as I like a good yeast bread Sourdough French Loaf is my very FAV.

I adding a link so you can read all about it & see the photos.

http://whatscookingamerica.net/Bread/Sou...

Answer 3

first off, "wild yeast" is completely correct.

the way to get it started is to take flour, water, and squeezed washed grapes, stir them up, then leave them in a bowl.  after 24 to 48hrs depending on temperature, humidity, etc, the mixture will start to bubble and give off an alchohol-y aroma.  that means it's been colonized by yeast and has activated. if it turns blueish or greenish or has a foul odour, the wrong kind took hold and the mix has spoiled.

after that, you need to keep feeding the starter for about a week before you can actually use it.  you add flour and water in proportions according to the recipe you choose.  every now and then, you have to divide it and get rid of some.  traditionally, you would gift it to a friend, neighbour, or relative.

once the starter has reached a certain size and stage, you can use it in your bread.

there's another difference:  when using sourdough starter, all-purpose flour doesn't work too well because there's not as much gluten as there is in bread flour, aka "hard" flour.  use unbleached, as well, for that characteristic creamy colour.  when kneading, you don't do that pansy massagey-rubby deal.  you scoop the dough up, twist it in the air, and WHACK it down on the counter.  the harder you do it, the more you activate the gluten and the better the  yeast can do its job.

ancient egyptians used the sourdough method - they would put the dough in clay pots up on the rooftops and leave them there.  they called it "sun bread".

gold miners in the yukon used to keep sourdough starter in battery acid jars.  they kept them going for years, even decades, and it was not uncommon for them to be passed down to heirs in a will.  sourdough for a miner was more than just the means to make an artsy fancy bread loaf - it was the means to staying alive.

Answer 4

I am actually making some now.  It is from a starter that is kept constantly (yeast cells in a jar).  You need to feed it flour or fresh dough daily.  Adding some of the last batch to the starter is comonly refered to as the sour process, which is how sour mash whiskey works.  It helps keep some consistancy in the flavor since the yeast is always evolving.  By adjusting the amount of starter you remove during the refreshing prossess you can make the next batch more of less tart.  This is from acidic acid (think vinigar), alcohol, and dead yeast cell buildup in the starter.  It is a lot of fun, and if you work it right, you can make fresh bread every day with sour dough starter.  

Also, sour dough is normally from a capture of wild yeast from the air.  Each area of the world has different wild yeasts that produce different flavors.  San Fransisco is known for their yeast, thats why San Fran sour dough is so famous.

Answer 5

It's made from a "starter".

A starter is flour, water and yeast. When combined the yeast feeds on the starter releasing a gas that over time adds a sour taste.

It usually takes a day or two.

Answer 6

In most breads as well as the usual loaf of white bread,yeast is the active ingredient which rapidly multiplies to make the dough & resultant loaf rise.

Sourdough also depends on yeast but the process is different,yeast present in the rising dough is preserved & replenished ,a small amount goes into a flour base raising a new batch of starter,it is this almost ever continuing process of keeping the yeast going that is responsible for the distinguishing & unique flavour of sourdough bread .

Answer 7

A different bacteria is used to create the sour taste.