Thierry Cauet has a problem. This instructor-brewer at the ESAT des “Papillons Blancs” in Lille produces a beer under the “Léonce” brand. But that day, as he uncapped a bottle and poured its contents into a glass, he made a sad observation. “Normally, we should have a head of foam of 1 to 2 cm,” he points out above the orange liquid. But there is nothing there. This bottle is therefore not marketable. »
Fortunately, he may have a solution. “This defect is generally due to a lack of protein.” As he walks towards his stock, he shows a large bag of cereal. “It’s barley malt, used in most beers but not particularly high in protein.” Instead of using 100% in his brew, he will replace 20% with wheat malt because “commonly used in white beers, it provides more protein”.
In its mash tank, the cereals are mixed with hot water. It smells like breakfast! Starch breaks down into sugars and proteins. A few hours later, this must, a “sweet juice”, is transferred to a fermentation tank where the yeast will transform the sugar into alcohol and small bubbles of carbon dioxide. We get beer! And the proteins are still present in the drink. The brewer takes a defective bottle and a new bottle and serves them at the same time in two glasses. On the left, the beer still has no foam.
But to the right... Once the beer is poured into a glass, the gas bubbles rise to the surface and cling to the proteins to form a whitish layer: this is the head of foam! “Both beers are equally good but consumers need the product to meet an aesthetic standard,” comments the brewer.
In fact, in the rest of the report with Théodore Becquart, agronomist expert in beer at the head of Brewing Theory, we will learn that the appearance of beer actually corresponds to a cultural cliché: in the south of England, we prefers it without foam. As for Laurent Cicurel, co-founder of the beer bar “La fine mousse” in Paris, he will give three tips for serving beer well. Finally, head chef Chloé Charles, from Lago, still in Paris, will reveal during a blind tasting that beer with foam is clearly the best. Press “play”!