From barley to beer: advances in brewing technologies for enhanced ethanol production- a systematic review

The brewing industry, long celebrated for transforming beer from barley into one of the world’s most recognizable beverages, is now entering a new era driven by scientific precision and process improvement. Modern breweries are turning to advanced fermentation, enzyme manipulation, and integrated bioprocessing strategies to elevate ethanol production while maintaining the craftsmanship and quality attributes central to brewing heritage. This systematic review, structured according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, compiles emerging industrial advancements that enhance ethanol production during brewing. Development in barley-based brewing focuses on starch structure and composition, varietal improvement through breeding, and pre-treatment approaches to accelerate the release of fermentable sugars. Process refinements in malting, mashing, adjunct use as substrates, and metal ion supplementation are critically analyzed for their impact on sugar release and fermentation performance. In parallel, innovative fermentation platforms, including batch, continuous, fed-batch, high-brewing, and co-culture systems that integrate non-conventional yeasts or bacteria with conventional yeasts, are being explored for their potential to enhance ethanol yield, fermentation duration, and product quality. This review also highlights automation, enzyme-driven hydrolysis optimization, advanced fermentation strategies, and machine-learning-assisted process control as transformative tools shaping the next-generation of brewery-integrated ethanol production. Collectively, these synergistic developments position barley at the forefront of advanced brewing-centered ethanol improvement, reinforcing the brewery as both a cultural tradition and a modern bioprocessing system.