Introduction

Abstract

This book is a personal appreciation of yeast. The primary objective of it is to compare and contrast the characteristics of brewing and distilling yeast cultures in a single document because the two types of yeast have much to learn from each other but there are differences! Yeasts are unicellular fungi, and they are economically the most important grouping of microorganisms employed on this planet, with alcohol as the major product. Although the focus here is on fermentation produced by yeast from a variety of substrates, yeast is a eukaryote—organisms (mammals, plants, fungi, etc.) whose cells contain a nucleus and other structures (organelles) enclosed by membranes. The primary differences between brewing and distilling production are discussed. Although Scotch whisky is an important distilled product, it is not the only one. Also, industrial fermentation ethanol production is becoming increasingly important. This development has resulted in considerable advances with yeasts that metabolize a plethora of substrates such as hydrolysed starch and cellulose/hemicellulose (pentoses and hexoses), inulin, sucrose, lactose, etc.