Shear Rates During Brewing Operations
MBAA TQ vol. 41, no. 3, 2004, pp. 241-247 |
VIEW ARTICLE Peer-Reviewed Paper
R. A. Speers, S. J. J. Patelakis, A. T. Paulson, and R. Oonsivilai. Department of Food Science and Technology, Dalhousie University, P.O. Box 1000, Halifax, NS, Canada B3J 2X4.
Abstract
The objective of this study was to determine the average shear rate that wort and beer are subjected to during transfer between unit operations in the brewery. To carry this out, a survey of pipe and flow characteristics was undertaken at a typical Canadian brewery. The information gained from this shear rate survey helped to establish a shear rate of 400 s(^�1) as an appropriate shear rate to perform the rheological measurements. It is important to note that wort and beer containing beta-glucans and other colloids, such as yeast flocs, are very sensitive to shearing action, which, in turn, affects their filterability and apparent viscosity. Consequently, this information would be useful to brewers for determining the location in the process in which to focus their attention to reduce the overall shearing action on these fluids.
Keywords: laminar flow, shear rate, turbulent flow, wort viscosity
S�ntesis
El objetivo de este estudio fue determinar la tasa media de las fuerzas de corte (cizalla) a las que son sujetas el mosto y cerveza durante las transferencias. Se hizo un levantamiento de las tuber�as y caracter�sticas de flujo en una cervecer�a t�pica en Canad� y la informaci�n recabada ayud� determinar que una tasa de fuerza de corte de 400/s ser�a un valor apropiado para la realizaci�n de las mediciones reol�gicas. Es importante notar que mosto y cerveza con beta-glucanos y otros coloides (tales como fl�culos de levadura), son muy sensibles a la acci�n de cizalla, afectando su filtrabilidad y su viscosidad aparente. Esta informaci�n deber�a ser de utilidad a los cerveceros para determinar adonde en el proceso se deber�an enfocar sus esfuerzos para reducir la acci�n global de corte en estos l�quidos.
Palabras claves: flujo laminar, tasa de fuerza de corte, flujo turbulento, viscosidad de mosto
