Efficient and cost-effective monitoring of beer filtration

Reliable and effective filtration is essential for clarity and taste, but also crucial for stability and ultimately the shelf life of beer. Final filtration of the finished product is usually carried out using layer or candle filters, or cross-flow filter systems.

Large industrial breweries with fully automated processes typically monitor the filter function and, at the same time, the dosage of filter aids made from diatomaceous earth, PVPP and silica gel using special turbidity sensors with a second measuring angle. For cost reasons, small and medium-sized breweries often do not use inline monitoring of beer final filtration at all. This is ensured by visual inspection or manual sampling.

In operations of this size, however, the filtration and stabilising agents are usually mixed in the same dosing vessel, or cross flow filter systems without diatomaceous earth are used. A second angle is therefore not necessary for pure filter monitoring. For precisely these breweries and applications, a special test setup has now proven that the ITM-4DW four-beam turbidity sensor can offer equivalent, reliable filtration monitoring at a significantly lower cost.

A test was conducted in collaboration with a brewery in the Netherlands, comparing an ITM-4DW turbidity meter with a competitor's device with 90deg and 25deg angles. Various liquids were pumped through a pipe sequentially and the values measured by both sensors were recorded in succession. The liquids used were: water; water with yeast, various concentrations; unfiltered beer; filtered beer; filtered beer with PVPP, various concentrations; and filtered beer with silica gel and diatomaceous earth, various concentrations.

Both sensors responded equally in all tests. In the case of filtered beer, both showed a correct flat line. With each change caused by the addition of yeast, PVPP or silica gel/diatomaceous earth, both sensors reliably showed a deflection in the measurement curves. Regardless of the particle size, it can therefore be concluded that the ITM-4DW offers a solution for filtration monitoring that is absolutely equivalent to the reference sensor with 90deg and 25deg angles.

The tests carried out clearly confirm that the ITM-4 turbidity sensor - with its very high measurement sensitivity starting at 0 NTU - is a solution that is equivalent to but significantly less expensive than the much more expensive dual-angle sensors in many applications.

For breweries that use a candle or layer filter with diatomaceous earth, but do not need to measure the PVPP or silica gel dosage for filter media optimisation, the ITM-4DW offers a reliable and extremely accurately programmable monitoring function. An increase in yeast, diatomaceous earth, PVPP or silica gel concentration due to a malfunction in the filtration system is measured reliably with high precision and triggered as an alarm.

For breweries that use cross-flow filtration without diatomaceous earth as a filtration aid, the ITM-4DW can also be used to create automated process monitoring. Any malfunction is detected, as the corresponding turbidity values also increase in this case and are immediately determined with superior measurement sensitivity. In both applications, the ITM-4DW enables breweries to implement cost-effective, yet highly accurate and reliable automated inline process monitoring against filter breakthrough.

In addition, the measurement technology with a 90deg/180deg measurement angle ensures complete compliance with quality standards (haze monitoring according to EBC/MEBAK). Previously required random samples or visual inspections can be completely eliminated. The use of an ITM-4DW can thus reliably counteract quality reductions and reduced stability and shelf life in beer.