All about Yeast
What is Yeast and why is it useful?
Yeast is classified as a fungus, a single-celled organism related to mushrooms. Wild yeast spores are all around us and constantly floating in the air and landing on uncovered foods and liquids. No one is sure when these wild spores first interacted with foods but it is known that the Egyptians used yeast as a leavening agent more than 5,000 years ago. Some historians believe that the action of yeast was probably noticed when bread dough was accidentally forgotten and left too long before baking and the lighter, fluffier bread that resulted became very popular.
Back in the time of Chaucer, the action of yeast in ale was so mysterious that the foam was simply called 'godisgoode', because its powers were perceived to be a miracle. The truth would have to wait until the mid-19th century and the discoveries of Louis Pasteur who proved that yeast is alive.
Scientists have identified over 600 different species of yeast since then, although some experts believe that the ones discovered so far may only represent 1% of the total varieties of yeast!
So, yeast is a living, microscopic, single-celled organism. To multiply and grow, all yeast needs is the right environment, which includes moisture, food (in the form of sugar or starch) and a warm, nuturing temperature. New yeast cells pop out of the side of old ones. If conditions are right, one single yeast cell can multiply to become the centre of a large clump of yeast cells in a very short time.
As it grows, yeast converts its food (through a process known as fermentation) into alcohol and carbon dioxide. This trait is what endears yeast to winemakers, brewers and bread bakers. In the making of wine and beer, the yeast's manufacture of alcohol is desired and necessary for the final product and carbon dioxide is what makes beer and champagne effervescent (bubbly). The art of bread making needs the carbon dioxide bubbles produced by yeast in order for the dough to rise.
We use yeast in the manufacture of our organic ale and lager. By 2012 we will also be using it to produce our own equivalent of Champagne from the organic grapes we grow!