BrewingScience issue March/April 2025 out now

Nuremberg | The latest BrewingScience issue March/April 2025 is out now. The scientific online-journal BrewingScience features peer-reviewed scientific papers with impact on the brewing industry. The latest issue has been sponsored by Hopsteiner. The brief article abstracts below provide a good initial overview of what you can expect in this issue.

Comparative study on the effect of mild temperature conditions in fractionated sterilization of carrot juice on microbiological stability and sensory properties (Weishaupt et al.)

Carrot juice is valued for its high vitamin and antioxidant content, necessitating gentle thermal processing to preserve these nutrients. Its slightly acidic pH value requires a two-step heating process, warranting optimization to enhance product quality and resource efficiency. This study investigated the impact of varying the first heating step between 100 and 130 °C on chemical, sensory, and microbiological parameters.

While other chemical parameters remained stable, lactic acid content increased significantly from 55 to 1405 mg/L over downtimes, highlighting the influence of external factors that could not be influenced within the investigations. Lower heating temperatures compromised microbiological stability, with spore-forming bacteria (5 colony forming units per 20 mL) detected at just a 10 °C reduction. Sensory quality showed minimal change, with descriptive analysis identifying only 3 respectively 4 significantly different attributes out of 19 across the factors experimental parameter setting and technical repetition. The quality of raw materials had a more pronounced impact on sensory outcomes than the heating temperature.

This study concludes that adjusting the first heating temperature has limited benefits for sensory quality but risks microbiological safety. Emphasis should therefore be placed on ensuring high-quality raw materials and consistent raw juice properties to maintain product quality.

Hot steep malt sensory evaluation method combined with check-all-that-apply – an approach for barley (hordeum vulgare l.) malt characterisation and quality control? (Häge et al.)

The Hot Steep Malt Sensory Evaluation, a method approved by the American Society of Brewing Chemists, was combined with the Check-All-That-Apply (CATA) method to assess the flavour profile of brewing malt. Ancient spring barley varieties (Hordeum vulgare L.), including Mahndorfer Hanna, Kraffts Riedgerste, and Alpine Pfauengerste, alongside a modern spring barley variety from the 2020 harvest, were malted with a standardised, small-scale malting process. Kilning was performed to produce Pilsner pale malt.

The results of this study demonstrate that the Hot Steep Malt Sensory Evaluation, in conjunction with the CATA method, is an effective tool for differentiating the flavour characteristics of brewing base malt due to its simplicity and rapid execution. Both methods also proved to be suitable for detecting off-flavours in base malt. However, successful implementation requires the identification of relevant attributes and sensory training of panellists. Consequently, these methods are highly applicable for quality control within malt houses and breweries to assess malt quality. Both methods combined might improve quality control even in small-scale breweries.

Utilisation of bubble formation for energy-efficient wort boiling while maintaining high wort quality (Grotenhoff, Becher)

Reducing primary energy consumption is a significant challenge in modern beer production. This study examines a patented boiling system that reduces this energy demand by significantly lowering the evaporation rate without negatively affecting relevant wort quality parameters compared to a state-of-the-art boiling system.

The wort is heated in an external boiler and recirculated through nozzles at the bottom of the wort kettle. There, the change in pressure conditions results in the formation of bubbles. These bubbles rise, support uniform homogenization of the wort, and allow the expulsion of volatile components such as DMS-free. Trials in a 10 hL pilot plant show that primary energy consumption during wort boiling can be reduced by 23 % while maintaining MEBAK quality parameters such as TBI, DMS-free, coag. N, etc.

The results highlight the potential of this system to make a significant contribution to sustainable beer production and open up perspectives for the development of further energy concepts that were previously limited by a required minimum evaporation rate of approx. 4 %.

The full articles can be read online at brewingscience.de/.