While the quality of your favourite tipple isn’t under threat from climate change, heat stress may have an impact on beer production, says University of Queensland food and nutrition scientist Dr Glen Fox.
“While we’ve noticed heat and drought stress produces a change in the starch properties of the barley used in beer production, brewers will always ensure a constant quality of their golden beverage,” Dr Fox said.
Beer is made from barley and other grains such as wheat or sorghum, along with hops for bitterness and aroma, and yeast is used for fermentation.
But heat and drought stress are impacting on the composition of these grains during the critical ‘grain fill’ period, the final stage of growth in cereals.
“Grain fill is where the grain is getting nice and plump just before maturity. There are also hundreds of compounds going through some metabolic change and a lot of those systems are all very sensitive to temperature,” Professor Fox said.
He said European researchers were noticing the effect as well.
“From an Australian perspective, we are seeing quite severe heat shocks much earlier in spring and that is having an impact on grain fill efficiency,” he said.
“We are still trying to understand the impact of this but what we are seeing is that the heat stressed grain requires a higher temperature to make all of its grain components soluble in the initial stages of brewing. This can reduce efficiency.”
Dr Fox said it was not so much a question of climate change impacting on the barley yield, or its even protein content, rather the grain composition.
“The risk for maltsters and brewers is that the barley might meet current specifications but does not perform the same in production, and this could cause problems in malting and brewing. But maltsters and brewers will always strive to ensure consistency of their products.”
Dr Fox said his message to industry was to also consider grain composition and do some additional testing rather than risk finding problems further downstream in the brewing process.
“Barley growers do an amazing job but the challenge for them will be to potentially select varieties that might flower and mature a little bit earlier to reduce the risk of suffering some sort of stress event during grain fill. Yield is absolutely important but maltsters don’t buy barley on yield, they buy on quality.”
“Also our barley breeders investment enormous resources to develop high yielding varieties with the required quality. Climate change unfortunately is presenting extra challenges for everyone.”
Dr Fox said climate change impacts such as heat and drought stress could also impact on the nutritional profile of the grain.
“This also poses a risk for grain food industries as well, like the baking industry.”
Research contact: Dr Glen Fox, Senior Research Fellow, QAAFI Centre for Nutrition and Food Sciences, The University of Queensland, T. +61 7 4639 8830 or T.+61 7 54601 594, E. gpfox@ucdavis.edu or E. g.fox1@uq.edu.au
Media contact: Margaret Puls, QAAFI Media T. +61 (0)419 578 356, E. m.puls@uq.edu.au
This research is supported by the Grains Research and Development Corporation.
