Researchers in Italy have developed a technique that promises to upend the age-old process of brewing beer.
The key is cavitation—the formation and collapse of tiny bubbles in a liquid. They’re created as a rotating object like a propeller moves through the liquid, creating a wave of low pressure at the tips. At the most extreme points in that low pressure, the liquid boils, creating small bubbles that soon collapse in a burst of heat and pressure. It’s that combination that could eliminate the need for an entire step of the brewing process.
Beer is traditionally brewed in four steps, starting with the creation of the wort from malted barley soaked in water. (The barley is often milled to increase the efficiency and efficacy of this process.) Next comes sparging, where the liquid is then drained and the barley washed. The wort is then boiled before yeast is added to ferment the liquid into beer.
The team, led by Lorenzo Albanese at the Institute of Biometeorology in Florence, Italy, introduced cavitation in the first step, when the barley is steeping in the water to make wort. That one small addition led to a cascade of changes. MIT Technology Review has more:
The first advantage is that cavitation pulps malted barley and so removes the necessity for it to be milled in advance. “Dry milling of malts becomes irrelevant with the new installation, since malts are pulverized by the cavitational processes down to less than 100 µm in size within a few minutes,” say Albanese and co. This also increases the biodegradability of the spent malt, which is a waste product of the beer-making process.
Cavitation also increases the rate at which starch passes from the pulverized malted barley into the wort. This process is so efficient that little if any starch is left in the malt at the end of the process.
That has significant implications. It means that the process of sparging—the washing of the malt to remove trapped sugar and starch—becomes entirely unnecessary.
In addition to removing the sparging process, cavitation also lowered the temperature at which the malt’s starch is transformed into sugar, and it eliminated the need to boil the wort with hops—the process only needed to take place at 172˚ F.
The end result was a more efficient brewing process. By lowering temperatures and eliminating the sparging step, Albanese and his colleagues say their new technique used 30% less energy than before and took less time. Perhaps most importantly, they report that the beer tastes as good as any other brew.