The wonder of yeast

bread that has been kneaded and is ready to rise

Yeast is an amazing organism.  Without it we wouldn't have rising doughs that give us sandwich breads and cinnamon rolls, vats of mashed fruits and their juices that become wines, and so many other food products.  It does this by a process called fermentation which is basically the breaking down of larger molecules into smaller more flavorful ones.  It doesn't matter whether it's bread that is rising, fruit juice that is developing into wine, cabbage becoming kimchi, or any other foods created by fermentation, the process is essentially the same.

bread that has risen in the bowl

With bread, when flour and water and yeast are combined, large starch molecules in the dough start to break down into simple sugars.   Ethyl alcohol and carbon dioxide are produced as part of this process as well as other byproducts such as organic acids and amino acids.  When the dough is kneaded, gluten is developed which strengthens the dough so that gases can be trapped inside, and so the dough expands, or rises.  All the various byproducts that result add flavors to the dough as well.  Without yeast, our culinary world would simply not be the same.

plastic wrap showing pressure inside the bowl after the dough has risen

Yeast is a fungus.  It's in the air.  It's on the surfaces of fruits.  It's in the soil.  It's found just about everywhere in nature.  

the final product after the yeast does its work

Thank goodness we have yeast.  Without it, our culinary world would simply not be the same.