Sector | Filtration A focus on Zagrebačka Pivovara’s investment in sterile filtration

AUTOMATE FILTRATION

WHEN CROATIA’S ZAGREBAČKA PIVOVARA MADE THE DECISION TO EXPAND ITS RANGE OF NONPASTEURIZED LAGER, THE NEED FOR A STERILE FILTRATION SOLUTION CAME WITH IT. REQUIRING A SYSTEM THAT COULD BE EASILY INTEGRATED INTO ITS SITE IN ZAGREB, IT TURNED TO AGIDENS AND PARKER BIOSCIENCE FILTRATION TO GET THE JOB DONE.

Founded in 1892, Zagrebačka pivovara in Zagreb was the first industrial brewery in Croatia and is synonymous with the country’s brewing industry. It was acquired by Molson Coors in 2012 and remains the leading producer of beer in the Croatian domestic market.

The brewery wanted to expand its range with a premium, non-pasteurized lager – and therefore needed a sterile filtration solution which could be easily integrated into its site in Zagreb. This challenge was taken up by a partnership between Agidens and Parker Bioscience Filtration. Belgium-based automation and process engineering company Agidens has a 30-year track record in providing turnkey automated solutions to the brewing industry, while Parker Bioscience Filtration has five decades of experience in working with the international food and beverage sector and offers a wide range of filtration solutions to breweries. In 2018, the two companies announced a partnership, which was created to enable the global brewing industry to access systems which integrated Parker Bioscience Filtration’s microfiltration solutions with Agidens’ automated processing technology.

Agidens offers a platform of cold stabilization modules to suit a range of beer flow capacities and specifications, as a more efficient alternative to pasteurization.

And Zagrebačka pivovara has been one of the first breweries to have seen the results of the collaboration. Drawn to Agidens because of the company’s extensive expertise in cold stabilization technology, Zagrebačka pivovara commissioned Agidens to implement a Cold Stabilization Module (CSM) at its brewery site. The CSM uses Parker Bioscience Filtration’s Prepor NG and Bevpor BR filters in a combination to achieve microbial stabil

Zagrebačka pivovara commissioned Agidens to implement a Cold Stabilization Module (CSM) at its brewery site

ity whilst protecting the taste characteristics of the premium lager. Sterile filtration solutions provided by Parker Bioscience Filtration are designed to allow brewers to significantly reduce the costs of microbial stabilization while protecting the beer’s sensory appeal.

Parker Bioscience Filtration’s Bevpor BR range of filters have been constructed with a unique Polyethersulphone (PES) membrane, offering a long service life and therefore a highly efficient and low cost of operation in sterile filtration of beer applications.

The company’s Prepor NG filters have been specifically developed to remove yeast and particulate such as filter aids and haze components. This superior level of retention ensures that a consistent quality of brew is delivered to bright beer storage whilst also offering a greater level of membrane filter protection during cold stabilization.

In just five months, Agidens’ engineering team was able to provide a tailor-made CSM solution that was integrated into the brewery’s existing production line. The CSM installation consists of three modules: a filtration skid, a distribution cluster and a CIP skid - for a total length of 6.75 metres. The site was only accessible via a small elevator which meant that the CSM had to be custom-designed, disassembled and transported before it could be rebuilt and installed on site. Agidens used the flexible software platform Siemens TIA for this CSM. This state-of-the-art platform lends itself perfectly to modular skid construction, such as the usage of the standard filter skids, simplifying maintenance and offering possibilities for expansion.

The CSM 12-250 installed at the Zagrebačka pivovara brewery filters an average of 250 hectolitres of beer per hour. Commenting on the installation, Tomislav Rorbach, process optimization rngineer at Zagrebačka pivovara, said: “The cooperation with Agidens was flawless and they have fully met our expectations with their CSM module.”

Lee Pattison, product manager for food and beverage at Parker Bioscience Filtration, added: “We’re delighted that our partnership with Agidens Process Automation has been able to create an effective solution for Zagrebačka pivovara. “It is an example of how breweries are able to tap into Parker Bioscience Filtration and Agidens Process Automation’s combined expertise in order to access innovative sterile filtration technology.

“By using cold stabilization modules in their processes, breweries can benefit from the numerous advantages that ster

ile filtration has over pasteurization, such as reducing product losses and energy costs, while protecting taste from the effects of heat treatment and increasing shelf life.

“The microbial stabilization of beer is of critical importance for the shelf-life of beers and an increasing number of brewers are turning to sterile filtration as a reliable method to ensure a longer shelf-life of their packaged beer.

“Many brewery operations have been moving away from flash pasteurization due to its negative impact on the flavour profile of the end product and the many advantages offered by sterile filtration.” According to the manufactyrer, the sterile filtration process is gentler, compared to the harsh process of flash pasteurization and this helps the beer to retain its unique and desirable characteristics more efficiently than beer stabilized through flash pasteurization.

Other advantages include the performance of sterile filtration which can more easily be monitored, because of the relative simplicity of cold stabilization systems. While the filters used in sterile filtration minimize adsorption of desirable components and help to protect beer head retention Beer losses when using sterile filtration can be significantly lower than flash pasteurization.

A ROBOT NOSE FOR A TRUE BREW

THE AROMA OF BEER IS A KEY INDICATOR OF ITS QUALITY, NOW NEW TECHNOLOGY CAN ‘SNIFF’ A BEER TO HELP BREWERS CREATE TOP NOTCH TASTY BREWS AND INNOVATIVE FLAVOURS. CLAUDIA HOOPER REPORTS FROM THE UNIVERSITY OF MELBOURNE

Is that pine or citrus notes in the beer? Coffee or chocolate? If the best-trained nose can sometimes have difficulties, is little hope for the rest of us?

However, enticing aromas are essential to the development of a superior beer and getting them right requires skilled personnel and costly equipment. This is no problem for big beer, but what about microbreweries that operate out of warehouses in the ex-industrial suburbs?

University of Melbourne researches from the Faculty of Veterinary and Agricultural Sciences and the Melbourne School of Engineering have developed a low cost and portable ‘electronic-nose’, or ‘e-nose’, that uses machine learning to quickly assess beer quality based on its aroma. Their report, “Development of a low-cost e-nose to assess aroma profiles: An artificial intelligence application to assess beer quality” has recently been published in the research journal Sensors and Actuators B: Chemical.

The Australian designed device is portable, allowing brewers to use it for rapid and reliable quality assessment on the production line. It also has the potential to be used to assess other food and beverages at all stages of production and has already been tested to detect smoke taint in wine.

This has been a huge problem during the last two years with major bush fires in both Californian and Southern Australia wine growing regions. While the fires can destroy vines, smoke from nearby fires can taint the grapes, making them worthless for wine.

The development of off-aromas or off-flavours in beers can occur particularly in breweries that don’t use pasteurisation. The partial sterilisation that comes through pasteurisation isn’t necessary to guarantee the safety of beer as it is a fermented product, and the process can modify aromas. But on the plus side pasteurisation can reduce the risk of aroma and flavours going ‘off’. With consumers demanding more novelty, brewers are responding by experimenting with different flavour profiles – milky stouts, cherry and honeycomb beers and even pickle. In an increasingly innovative environment like this, it’s important to develop methods that can assess aroma both during and after boiling (with the addition of hops) and fermentation.

Gas chromatography instruments that analyse the vapours given off by a compound can be used to do this, but it’s costly, time-consuming and involves sending samples away for assessment. In beer, the aroma alone is a fairly reliable indicator of quality. This is due to the close link between our senses of smell and taste. But in a small brewery, there may only be one or two people – including the master brewer – conducting aroma testing sessions for each batch.

The portable ‘electronic -nose’ uses machine learning to assess beer quality.

The process can be imperfect and takes time, but it’s also ultimately highly subjective. New and emerging technologies are able to get around this. Sensors, robotics and machine learning have been brought together to reduce time spent assessing food quality while providing a less variable test.

“Our study shows that this technology can be used to assess quality in the field. It’s a first for a genuinely portable device,” according to lead authors Associate Professor Sigfredo Fuentes and PhD candidate Claudia Gonzalez Viejo. Her research started with a University of Melbourne student project that involved using Legos to create a device to measure bubbles in drinks. The level of bubbling is an important quality of drinks, with consumers preferring medium-sized bubbles in products like sparkling water and in the foam for beer. “You can determine how much people will like a drink by the quality of the bubbles,” says Fuentes. “Bubbles and foamability and the stability of the bubbles are really important.”

In beer, the froth or foam created by bubbles helps to protect the drink from oxidisation that alters the flavour profile – this is why dark stouts like Guinness are often pumped with nitrogen to create a

fine foam on top to protect it.

“If you have a flat Guinness, it will oxidise, giving you off-flavours in five minutes,” says Fuentes. Measuring the bubbles and carbon dioxide led nicely into the next phase of Fuente’s research – adding additional sensors to measure other gases and determine how those bring about different aromas.

To investigate the effectiveness of the e-nose, the researchers conducted a study of 20 different commercial beer samples, covering a range of styles and fermentation types.

The variety in beer styles helped create a computer program that can detect different volatile compounds, reducing bias in the artificial intelligence software that was developed alongside the e-nose, which was built by Bryce Widdicombe and Dr Ranjith R Unnithan at the Melbourne School of Engineering. The e-nose – a small circuit board with a diameter of 92 millimetres – is placed face-down over a sample of beer in a beaker. The sensors can then measure the gases above the beer.

This data is measured in real-time, with the help of food technologist Amruta Godbole from the Faculty of Veterinary and Agricultural Sciences. The results were measured against a traditional sensory session conducted by twelve trained panellists. The panel assessed the intensity of different beer aromas – hops, spicy, floral, fruity, burnt sugar, grains, yeast, nut and carbonation mouthfeel. The samples were also measured using gas chromatography-mass spectroscopy (GC-MS). One of the objectives is to also use the data from the e-nose to aid in the creation of flavour profiles.

“With the e-nose, you just do a pour, and then you get all the data through the machine learning – you get the whole aroma profile of the beer with 97 percent accuracy,” says Fuentes.

The e-nose measures the peak area of different gases that are present in beer vapours before fermentation and afterwards. The sensors on the e-nose are calibrated to measure the presence of gases like carbon dioxide, ethanol, methane, hydrogen, hydrogen sulfide, carbon monoxide, ammonia and benzene.

There are different gases present as a result of different types of fermentation, like lambic beers. These beers are produced by spontaneous fermentation using wild yeast. This allows for the development of more gases and aromatics than beers from top (like ales) and bottom (like lagers) fermentation that use domesticated yeast varieties. The researchers hope to finesse the design further, making it smaller and integrating rechargeable batteries and WiFi to allow brewers greater flexibility, as the current version needs to be connected to power and a computer via USB.

But the potential applications of the device go beyond beer and identifying smoke taint to include building flavour profiles for sparkling wines and non-alcoholic beverages like coffee or tea. “The e-nose helps take a good deal of subjectivity out of things,” says Fuentes. “Manufacturers will be able to definitively say what is in each flavour profile and put that information on the product labelling.”

But will the e-nose replace a master brewer’s taste? Absolutely not, says Fuentes. “I find that brewers are not against technology. They embrace it.”