Warzenie słodu zielonego: rozwój procesu i wymagania techniczne procesu wydajnego pod względem zużycia wody i energii z pominięciem suszenia słodu

Celina Dugulin
University of Nottingham, Wielka Brytania

Słowa kluczowe: green malt brewing, energy efficiency

Climate change and the depletion of fossil fuel reserves have prompted energy intensive industries to reduce their energy usage and carbon emissions. In the UK alone, 1.5 million tonnes of malt are produced annually, with the accompanying emission of around 340 000 t CO2 per year (The Carbon Trust, 2011); an improvement in energy efficiency is required.

Omitting the kilning process would reduce the energy inputs required for malting. However, apart from being a dominant consumer of heat and electricity, the kilning process has many beneficial quality impacts, such as reduction of lipoxygenase, regulation of S-methyl methionine (SMM) levels, facilitating rootlet removal and most importantly in developing the characteristic flavours which malt imparts to beer.

The objective of this project is to evaluate the feasibility of brewing using freshly germinated (green) malt, with omission of the kilning step. Here we report the laboratory scale development of such a process to enable evaluation of the significant quality impacts on the brewing process and finished beer. Well-germinated malt is separated into endosperm-rich and husk/rootlet fractions, with only the endosperm-rich fraction being used for conventional mashing. Optimisation of the initial separation process has resulted in hot water extract values in the region of 71% d.b. Furthermore, the biochemical differences between green malt and kilned malt are characterised, with a focus on lipoxygenase activity, SMM levels and diastatic enzyme activities.

Subsequent laboratory scale brewing trials are underway in order to screen for significant taints or changes in processability when brewing using the innovative green malt process versus control brews using kilned malt or hammer-milled green malt. These findings will then form the focus for future process development.