Latest BrewingScience issue out now

Nuremberg | The latest BrewingScience issue 7/8 2025 is sponsored by Hopsteiner and contains articles on optimizing thermal product processing in oat drink production and technological strategies for controlling aldehyde formation in beer: a review of brewing-related flavour instability. The brief article abstracts below provide a good initial overview of the content.

Optimizing thermal product processing in oat drink production (R. Feilner, U. Bedoe, S. Hoeller, M. Engst, T. Runge, C. Nuber, S. Day, S. Lindtner, F. Lehnhardt)

Milk alternatives such as soy, almond, and oat drinks have become staples in supermarkets due to their health benefits, great taste and sustainability affects. An increasing number of breweries are entering oat drink production, as the manufacturing process closely resembles traditional brewing. This allows efficient repurposing of existing equipment such as mills, mash tuns, and storage tanks. For industrial-scale production, thermal preservation by direct heating is the preferred method to ensure microbiological stability while maintaining desirable sensory qualities and minimizing off-flavours. A key factor for cost-effective production is maximizing the operational time of the ultra-high temperature (UHT) process, minimizing interruptions for cleaning and sterilization. However, the formation of fouling layers in the high-temperature sections of the system – often within just a few hours – poses a significant limitation. The extent of fouling is strongly influenced by the upstream hydrolysis process.

This study aimed to investigate the factors contributing to fouling to enable precise adjustments to equipment and process parameters, as well as to optimize cleaning procedures (CIP). Therefore, oat drink was produced in-house from oat flour via enzymatic hydrolysis and subsequently subjected to direct thermal treatment at both pilot and industrial scales. The results demonstrated a clear influence of the applied temperature profile on fouling behaviour. Sedimentation characteristics, colour development, and sensory attributes of the thermally treated oat drink were evaluated.

Technological strategies for controlling aldehyde formation in beer: a review of brewing-related flavour instability (M. Ditrych, G. Aerts, M. L. Andersen)

Flavour stability is a critical quality parameter in brewing, with major implications for shelf-life, consumer satisfaction and global beer distribution. In particular lager beers are prone to flavour deterioration due to their delicate aroma profile. Essential to this deterioration is the accumulation of volatile aldehydes, which are primarily responsible for the stale flavour perceived in aged beer. These compounds originate from multiple chemical pathways, including Maillard reactions, Strecker degradation and oxidation of amino acids, humulones and lipids, all of which are influenced by raw material composition and brewing conditions.

This review presents a state-of-the-art overview of aldehyde-driven flavour instability in beer, highlighting the formation mechanisms and, in particular, the impact of brewing operations across the production chain. Critical control points are examined from malt modification, mashing temperature, wort boiling and yeast metabolism, through to downstream processing and packaging. Emphasis is given to the role of heat, oxygen and transition metal ions, alongside yeast activity and sulphite dynamics. Innovative strategies such as the removal of prooxidative metal ions, use of antioxidant-rich ingredients are discussed. Additionally, the review outlines advances in packaging technologies aimed at minimising oxygen ingress and light exposure. This review provides an up-to-date synthesis of brewing operations that affect flavour stability, offering a practical framework for mitigating aldehyde-driven staling throughout the beer production chain.