Haze: The lmportance of Being Earnest [About Zero]

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

Abstract
Measurement systems in the breweries no longer report data just to the operator and brewer; they now send data directly to automatic control systems. This data is subsequently placed in company-wide written reports. This puts extra emphasis on accuracy and calibration, as establishing the instrument zero (along with span) is the basis of brewery measurement systems, whether they report temperature, alcohol, flow, or turbidity. In this work we show errors that do occur while adjusting instrument zero during calibration of haze meters-errors that occur even when the technician follows the manufacturer's recommendations. Examples gathered are from scatter turbidity/haze measurement. The experimental data shows examples of how zero adjustment errors can cause undetected inaccuracies in over 100% of the readings. Guidelines for good practice are discussed, including suggested pro- cedures/protocols for determining true haze zero without removing sensors, emptying pipes, using potable water, or packing the pipe with ultra-pure water.
Keywords: Beer Haze, Haze Standards, Haze Meter Calibration, Haze Measurement  

Sintesis
Los sistemas de medicion en la cerveceria ya no solamente repor- tan datos al operador y al cervecero. Ahora ellos mandan los datos directamente a sistemas de control automaticos y ponen los datos directamente en reportes para toda la companfa. Esto pone enfasis extra en la precision y calibration. El establecer el instrumento cero (asi coma el rango) es la base de los sistemas de medicidn de la cerveceria, ya sea que reporten temperatura, alcohol, flujo o turbiedad. En este trabajo nosotros mostramos errores que ocurren cuando se ajusta a cero durante la calibration initial de los medidores de la cerveceria, sun cuando el tecnico sigue las recomendaciones del fabricante. Se incluyen ejemplos de la medida de turbiedad/ niebla. Datos experimentales de la cerveceria muestran ejemplos donde errores en el ajuste a cero pueden causar errores no detectables en mas del 100% de las lecturas. Las norrnas para la buena prhctica son discutidas, incluyendo protocoloslprocedimientos sugeridos para determinar el verdadero cero de la niebla sin remover sensores, vaciar tuberias, usar agua portable o llenar las tuberias con agua ultra pura.