Approaches to Reducing Carbon Dioxide Emissions in the Malting Process.
-Brewing Performance of ‘Dual-S Barley’ Malt with 2 Days Germination Period-

Major Japanese breweries have set the goal of reaching zero emissions. The Sapporo group is aiming for net zero greenhouse gas emissions at its sites and throughout its supply chain by 2050. Production of malt consists of three main processes: steeping, germination, and kilning. Since these processes consume water and energy, shortening each process is expected to reduce the environmental impact (carbon dioxide emissions) during malting. A novel barley variety ‘N68-411’ was found to have an excellent balance of modification and seed dormancy, which is related to pre-harvest sprouting, and it has been shown that this barley has a rapid modification, which can shorten steeping time or germination days. We developed a ‘Dual-S (Sustainable care and Stable care) Barley’ by cross-breeding that has both characteristics of ‘N68-411’ and the LOX-less (lipoxygenase-1-less) barley, which can improve flavor stability by reduction of beer deteriorating substances such as trans-2-nonenal. This ‘Dual-S Barley’ was used to produce malt with 2 days germination period (no gibberellic acid treatment), and ‘Satuiku 2 go’, which is a general Japanese LOX-less variety, was used for control malt with 6 days germination in micro-malting apparatus. Malt analysis indicated that ‘Dual-S barley' showed adequate modification with higher KI and lower β-glucan than those of control barley variety, even though the germination period was 2 days. Pilsner beer was brewed (100-liter scale) using 50 % malt each of ‘Dual-S Barley’ and control. ‘Dual-S Barley’ did not significantly affect the mashing or fermentation behavior compared with control. Beer analysis and sensory evaluation showed that no major defects were observed in ‘Dual-S Barley’. These results suggest that ‘Dual-S Barley’ could contribute to both carbon dioxide emission in malting process and flavor stability in beer.