The Anton Paar Beer Monitor: a modern classic

The Beer Monitor is the result of over 20 years of working experience in inline and laboratory beer analysis, based on over a thousand samples covering products ranging from alcohol-free beers to double bock. It uses proven density and sound velocity measurement combined in a compact sensor with a hygienic stainless steel housing. Combined with an additional CO₂ sensor from the Carbo series, a complete beer and CO₂ measuring system is created.

Density and sound velocity are a good example of how the physics of the measurement principles work optimally. The alcohol strongly increases the sound velocity and decreases the density. Extract increases mostly density and has only a moderate influence on sound velocity. All sugars affect density equally and cumulatively allowing for a highly accurate measurement of the total extract. The only process parameters which affect density and sound velocity are temperature and pressure. These influences are compensated for when the sensor is factory calibrated before delivery and do not change during the life of the instrument. The Beer Monitor software automatically determines alcohol, real and original extract using density, sound velocity, temperature and CO₂ values across a wide concentration range. Various beer-specific values such as apparent and real degree of fermentation, apparent extract, specific gravity, present gravity, calories and real extract to alcohol ratio are also provided.

Spectroscopic techniques like infrared (IR) or near infrared (NIR) absorption are extremely selective and accurate. Indeed, Anton Paar utilizes NIR absorption in the laboratory Alcolyzer Beer Analyzing System. Optical sensors are, however, more sensitive to process and environmental influences, especially temperature. Whereas density measures all sugars equally and cumulatively, IR/NIR cannot. Depending on the mash process, extract efficiency, enzyme activity, enzyme addition, and feedstock used the sugar composition changes continuously from batch to batch. The total extract is only as accurate as the sum of the various sugars measured, and these vary continuously under normal process conditions. A complex mathematical model requiring numerous laboratory measurements is used to calculate the cumulative extract content for each product.

Density and sound velocity measurement are therefore still proven modern classics which provide out–of-the-box quality and process control with no or little adjustments.

Typical areas of application include hot & cold wort (lauter tun, mash filter, kettle, whirlpool, wort cooler), blending & filtration and packaging (before the filler).