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Volume 37, Number 1, 2000, Pages 37-41

Automatic Yeast Pitching Control Using Cell Counting

By H. A. Teass, Jr. McNab, Inc., Mount Vernon, NY, USA. This poster was originally presented at the MBAA 112th Anniversary Convention, Keystone, Colorado, 1999.

Yeast pitching to start the fermentation in a mid size brewery is often a manual process involving assumptions of uniform distribution of yeast in the supply tank, as well as manual calculation of quantity of yeast required, and manual control of the transfer pump. In this work, a packaged/skid-mounted unit is used to transfer the correct number of cells for a given batch size. Components of the skid include a McNab HSA4 in-pipe cell counter, a magnetic flow meter, and a controller (or logic) unit. The existing brewery pump and hardware are used. An accessory labora- tory meter (CLB) may be used to verify accuracy. The brewer enters the number of gallons of standard yeast required for the batch size, and the skid turns on the transfer pump, counts the number of cells transferred, makes continuous "on the fly" correc- tions in the calculation, and turns off the transfer pump when the tar- get is reached. In this installation, the skid replaces the former volumetric method of measurement, correcting for variations in yeast concentration. Measurement of actual cells/ml in the fermenter at the start of fer- mentation shows a substantial reduction of variation in cells/ml at ini- tiation of fermentation.
Keywords: Yeast Pitching Control, Yeast Pitching System, Yeast Particle Counting, Automatic Yeast Dosing


El proceso de arrojar la levadura para empezar la fermentacion en una cerveceria de mediano tamafio es frecuentemente un product0 manual que involucra suposiciones de que la distribution de levadu- ra es uniforme en el tanque de abastecimiento, asi coma el calculo manual de la cantidad de levadura requerida y un control manual de la bomba para transferir. En este trabajo, una unidad skid/empacada es usada para transferir el numero correct0 de celulas para una reme- sa dada. Los componentes del skid incluyen un contador de celulas McNab HSA4 en pipeta, un medidor de flujo magn&ico y una unidad con- troladora (o logica). Se usan el equip0 fi'sico y la bomba existentes de la cerveceria. Un medidor de laboratorio accesorio (CLB) se puede usar para verificar la precision. El cervecero marca el numero de galones de levadura estandar requerida para el tamafio de la remesa y el skid prende la bomba para transferir, cuenta el numero de celulas transferidas, hate correcciones continuas de la calculaci6n durante el proceso y apaga la bomba para transferir cuando se alcanza la meta. En esta instalacion, el skid reemplaza el metodo volumetrico de medicion anterior, corrigiendo las variaciones en la concentration de levadura. La medida de las celulas actuales/ml en el fermentador al inicio de la fermentacibn muestra una reduction substantial de la variation de celulaslml al inicio de la fermentacidn.