THERE'S more to brewing than beer. A by-product of the process could be about to give an upgrade to a workhorse building material – red clay bricks. By blending in the grains left over from making beer, the bricks can be more environmentally friendly and better insulators.
Bricks are often impregnated with polystyrene as a way to enhance their heat-trapping abilities. This is appealing, because the bricks remain strong, and they can be built into energy-efficient buildings, says Eduardo Ferraz of the Polytechnic Institute of Tomar in Portugal. However, EU restrictions on carbon emissions have made it expensive to incorporate polystyrene and other synthetic materials into bricks.
Ferraz and his colleagues have now shown that brewery grains can be mixed into clay bricks to enhance their ability to trap heat, without compromising strength.
Spent grain for the process should be easily available, because commercial breweries produce huge quantities of it as a pulpy mixture that is usually used in animal feed or ends up in landfill.
With a clay paste containing 5 per cent spent grains, the team was able to create bricks just as strong as the conventional type, while reducing the amount of heat they lost by 28 per cent (Journal of Materials in Civil Engineering, doi.org/p6k). The reason for this, the team says, is that the grains make the bricks more porous, and so they trap more air, which increases heat retention.
One thing could stand in the way of using this process, though: the smell. Bill Daidone of the Acme Brick Company, one of the largest brick manufacturers in the US, says his lab abandoned experiments because the stench of the moist grains was overpowering. "We opened up the bucket and it was terrible," he says. This problem vanishes once the bricks are fired, though, says Ferraz.
Bricks that provide insulation without sacrificing strength could be a big boost to the brick industry, says John Sanders, a researcher at the National Brick Research Center at Clemson University in South Carolina.
"With the current concern for energy codes, I think the industry is open to change," Sanders says.
This article appeared in print under the headline "Brewing benefits? Alcohol, hangovers and better bricks"
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