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This review paper covers a variety of aspects concerning lauter turbidity and wort clarity that have been published in the past decades. The components of wort which are connected to an increased lauter turbidity, such as lipids and long-chain fatty acids, are presented as well as how the further steps of wort production, i.e. wort boiling and clarification, have an impact thereon. Besides the influence of lauter turbidity on wort quality, technical aspects affecting lauter turbidity are discussed by comparing different lauter systems such as lauter tun, mash filter and strainmaster. It is further highlighted, how lauter turbidity and its components influence fermentation performance and yeast vitality. Finally, the consequences of increased wort turbidity for the resulting beers in terms of flavour quality, flavour stability, nonbiological stability and foam stability are described.

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To gain further technological knowledge of mashing, pilot scale mashing trials were carried out varying mashing programme (upward /isothermal mashing), milling procedure, grist : liquor ratio, time of mash stands, and grist modification level (well and poorly modified malt). During mashing β-glucan, free amino nitrogen (FAN) and extract contents were analysed as key indicators for cytolysis, proteolysis, and amylolysis, respectively. The malt modification was of major impact for the β-glucan release in contrast to a variation of milling procedure and of grist : liquor ratio. Extended stands lead to increased final values only for poorly modified malt. Similarly, FAN release was predetermined by malt modification while variation of milling and of grist : liquor ratio was not relevant in contrast to stand extension. None of the variations applied influenced extract yield as long as gelatinization temperature was reached. Greatest gains occurred around 57°C. In conclusion, wort quality is critically determined by malt modification. Mashing with well modified malt in combination with short stands should result in a mash of low β-glucan and sufficient FAN level without losing extract yield. However, for poorly modified malt the variation of mashing parameters has an impact on the key indicators in which cytolysis plays the dominating role.