The basic science behind fermentation. This book will be of help to the intermediate or advanced homebrewer eager to fine-tune their output. Janson tries to keep the hard science to a minimum and explains terms and processes fully and clearly. Still, he charts a lot of molecular structures, but his explanations are so comprehensive and his perception of common home-brewing problems so canny that the technical material won't drive readers away.There is a great chapter on avoiding "off" flavors, and a section on evaluating beers. 117 Pages.