Measuring °Plato in brewing using Coriolis principle

Flow Measurement & Control

November 2002 Flow Measurement & Control

In the brewing industry, °Plato refers to the %-weight of sucrose in a 20°C sollution of the wort prior to fermentation. The measurement is derived from the density of the solution. This measurement is necessary in order for the brewery to optimise the extract concentration prior to boiling in the brew kettle and without such a measurement, it would be difficult to ensure product consistency. °Plato measurement also enables the brewery to monitor the boiling process and to measure the concentration of the wort transferred to the fermentation tanks.

Traditionally, measuring of °Plato was performed manually by analysing a sample of the wort in a laboraory. The sample is cooled to 20°C, the density is measured and the °Plato was determined either by using the °Plato table or a float weight calibrated to °Plato. The inherent problem with this method is that it is time consuming and can lead to inaccuracies caused by temperature or pressure changes or contamination of the sample.

The Massflo Coriolis mass flowmeter from Danfoss is a single pipe flowmeter which can be installed in a number of areas in the brewing process to automatically measure the °Plato. Density measurements are derived from the mass of the product flowing through the instrument. The unit can be installed between the lauter tun and the brew kettle, operating at temperatures from 60 to 80°C, to measure the total amount of the wort and its carbohydrate content (as sucrose). After the initial wort runoff from the lauter tun, the bed is flushed with water to remove the last of the wort.

During this operation, the instrument can monitor the decreasing sugar concentration, enabling the brewery to determine the optimum flushing cycle time.

The Massflo can also be installed at the brew kettle, where at temperatures up to 100°C, it can be used to monitor and control the boiling and evaporation process. Installed between the brew kettle and the fermentation tanks, the unit can be used to measure the total amount of wort and carbohydrate being transferred.

The advantages of automating the °Plato measuring process include the ability to respond quicker to changing process conditions, allowing the brewery to optimise the process and take corrective steps as problems occur, instead of having to wait for the results obtained from a laboratory sample.

The system also eliminates the problem of human error occurring in the analysis of samples. The Massflo can provide a °Plato measuring accuracy to within 0,1 °Plato. In addition to mass flow measurements (accurate to within 0,15%) and density (accurate to within 0,007 g/cc), the unit can also provide temperature measurements. The Massflo features stainless steel construction and a choice of sanitary fittings, making it ideal for applications requiring CIP and steam clean cycles and is available for pipe sizes from 15 to 80 mm. The unit also features Danfoss's Sensorprom technology which automatically calibrates and programmes the unit, making installation and commissioning quick and easy.

For more information contact Danfoss (Instrumentation Division), 011 803 8390.

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Flow Measurement & Control

Measuring °Plato in brewing using Coriolis principle

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