Monitoring & metering


Lautering Sparge water rinses the grains inside the lauter tun to complete the extraction of sugars, producing a clear wort with a concentration that gradually decreases during the rinsing. The refractometer continuously measures this concentration, allowing the detection of the appropriate shut-off point for rinsing, which prevents the excessive use of water and saves energy.


Wort boiling Once the sweet wort has been separated, it is pasteurised in a wort boiler or brew kettle, and this is the stage at which hops and other flavourings may be added. Wort boiling terminates enzymatic activity, preserves foam-positive proteins, evaporates unwanted flavour volatiles, and helps to form desirable taste and aroma compounds. It also brings the brew to the appropriate strength or gravity, so this is an extremely important stage in the brewing process. The refractometer is installed directly in the


wort boiler, providing continuous measurements of wort strength/gravity so that the brewer can determine exactly when the wort has reached the required strength. This improves beer quality and consistency, while helping to optimise brewing time and energy consumption.


Whirlpooling After boiling, the wort is transferred to a whirlpool, where solid particles (hop rests and coagulated proteins) are separated from the bitter wort. The whirlpool causes residual particles to coagulate and settle out of the liquid as a sludge known as trub, which is partially removed from the bottom of the kettle. It is important that the solids are removed quickly and effectively to produce a clear, bitter wort for transfer to the next stage, so a refractometer may be installed before and/or after the whirlpool.


Cooling Once boiling is complete, the wort is cooled by a heat exchanger which recovers some of the energy used to boil the wort. Refractometers can be installed in the outlet of the cooler as a quality control measure; ensuring that the bitter wort contains the correct level of dissolved solids before fermentation. Alternatively, or additionally, a measurement can be made after the boiler and prior to the whirlpool, to avoid the possibility of processing bitter wort that does not meet the required specification.


Fermentation During the fermentation process, yeast converts sugars and amino acids in the wort to carbon dioxide and alcohol. The gravity of the fermenting liquid is measured as the specific gravity, or relative density compared to water. In the brewing industry, this is mostly measured on the Plato scale, which is very similar to the Brix scale used by the wine industry. Spent yeast collects at the bottom of the


fermentation tank and is regularly removed, which helps to clarify the beer.


Instrumentation Monthly November 2021  


 


 











 


The density of the wort varies according to the


sugar content, so the density readings decline as fermentation progresses. The alcohol percentage can be calculated from the difference between the original wort gravity and the current specific gravity. Refractometers are therefore able to closely follow the fermentation process; providing brewers with real-time insights into the process, and allowing them to accurately determine when fermentation is complete.


Filtration and maturation Maturation includes all transformations between the end of primary fermentation and the removal of yeast from the beer. After fermentation, the beer is allowed to rest, so that any remaining spent yeast can settle out. However, a number of filtration techniques are often applied to further clarify the beer. This is the final opportunity to affect the quality profile of the beer - flavour, bitterness, odour and foam stability, clarity, colour, alcohol and gas content. All of which vary according to the requirement of the brand, so refractometers can fulfil a vital role in quality control.


Filling and CIP When the beer is ready for distribution it is packed in bottles, cans, casks and barrels which must be clean and sanitised. In addition, the internal surfaces of pipes, vessels, tanks and packaging equipment must be cleaned between batches and between different products. Known as Clean in Place (CIP) this protects the beer products from microbiological and chemical


contamination. In large modern breweries the cleaning processes are complex, so automation is frequently utilised to improve speed and efficiency, and lower costs. At the filling line, the refractometer instantly


detects the product-to-product and product- to-CIP cleaning interfaces, allowing efficient change-over between products or batches. The refractometer output signal can also be utilised for quality control monitoring, and to ensure correct product-to-packaging selection. The response speed of the refractometer means that the interfaces (between product/cleaning chemicals/water), can be detected very quickly, which avoids waste and ensures that no product contamination occurs. Continuous monitoring of packing and CIP


processes with the Vaisala refractometers therefore enables automation, reduces wastage and lowers costs and energy use.


Why use reFraCtometers throughout the breWery? In contrast with other methods, the main advantages of Vaisala’s refractometers are that they provide greater insight into every stage of the brewing process; they are not affected by suspended particles, bubbles or colour, and with the option of automatic prism wash with steam or high-pressure hot water, they are not affected by scaling or fouling. Each Vaisala refractometer is factory calibrated


for the full measurement range (e.g. 0-100 degree Plato), which means they can be freely interchanged between installation locations without parameter changes. Furthermore, the Vaisala refractometers do not require any routine recalibration or maintenance. In summary, it is certainly true that brewing


success is underpinned by passion, determination and innovation, but, with the help of refractometry, brewers can optimise their processes, reduce waste, lower energy consumption and rest assured that they will continue to produce consistently good quality beer.


Vaisala www.vaisala.com 45


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74