This review deals with beer filtration, which is an important part of today´s brewing technology. It describes the historical development of this separation technique, explains the basic definitions, methods of filtration using different filter materials, and specifies the haze particles of beer according to their size and physico-chemical properties. In addition to a general overview, it provides a summary of recent findings on the mechanism of filter fouling by yeast, colloidal particles, and macromolecules such as proteins or carbohydrates. Particular attention is paid to the influence of beta glucans, whose molecular weight, or their interactions with other beer components are more important than the total concentration. The review also contains information on ways to improve filtration efficiency, introduces new filter materials, and compares two of the most used filtration systems pre-coat filtration and membrane filtration in terms of sustainability and ecology.