History of Wine making

Introduction

Along with bread making, the use of the microorganisms called yeasts to produce wine from grapes is one of the oldest uses of microorganisms by man. The origins of wine making date from antiquity. Before 2000 B.C. the Egyptians would store crushed fruit in a warm place in order to produce a liquid whose consumption produced feelings of euphoria. The manufacture and consumption of wine rapidly became a part of daily life in many areas of the Ancient world and eventually became a well-established part of Classical civilization. For centuries, wine making has been an important economic activity. In certain areas of the world, such as France, Italy, and Northern California, wine making on a commercial scale is a vital part of the local economy (Mancuso, 14).

Discussion and Analysis

The agent of the formation of wine is yeast. Yeasts are small, single-celled fungi that belong to the genus Ascomycota. Hallmarks of yeast are their ability to reproduce by the methods of fission or budding, and their ability to utilize compounds called carbohydrates (specifically the sugar glucose) with the subsequent production of alcohol and the gas carbon dioxide. This chemical process is called fermentation.

Yeast cells are able to carry out fermentation because of enzymes they possess. The conversion of sugar to alcohol ultimately proves lethal to the yeast cells, which cannot tolerate the increasing alcohol levels. Depending on the type of yeast used, the alcohol content of the finished product can vary from around 5% to over 20%, by volume.

The scientific roots of fermentation experimentation date back to the seventeenth century. In 1680 Anton van Leeuwenhoek used his hand-built light microscopes to detect yeast. Almost one hundred years later the French chemist Antoine Laurent Lavoisier proposed that yeast was the agent of the fermentation of sugar. This was confirmed in 1935 by the examination of yeast vats with the greatly improved microscopes of that day.

In the nineteenth century the role of yeasts as a catalyst (that is, as an agent that accelerates a chemical process without itself being changed in the process) was recognized by the Swedish chemist Jons Berzelius. In the 1860s the renowned microbiologist Louis Pasteur discovered that yeast fermentation could proceed in the absence of oxygen. In 1878 Wilhelm Kuhne recognized that the yeast catalyst was contained inside the cell. He coined the term "enzyme" for the catalyst (Mancuso, 65).

In fact more than two dozen yeast enzymes ...