Wet brewers grain is the most important byproduct of beer production. Brewers grain is the malt residues remaining after the cooking process, after the majority of the sugar has already been extracted. Brewers grain consists chiefly of dietary fiber (30-50%) and proteins (19-30%), which are also primary nutrients in the context of human nutrition. This aspect makes brewers grain very attractive for use as an additive to enhance the nutritional value of foods. But despite its potential nutritional value, brewers grain is usually disposed of as livestock fodder. However, under the aspect of recycling, brewers grain represents an interesting byproduct with a high nutritional value. The addition of brewers grain in producing baked goods could be interesting for companies of various sizes.
Until now, the color and taste of brewers grain has set limits on its use as a partial replacement for flour. Because of its high moisture content, it is important that the brewers grain be stabilized using a sustainable process in order for it to be employed as a healthy food ingredient. Wet brewers grain obtained from the manufacture of barley malt beer and/or combined rye+barley malt beer was dried using a drum-type drying system (Fig. 1), making it possible to dry it in a short amount of time; this is also more energy-efficient and economically sustainable. The initial moisture content of the brewers grain was 68-70 %. The drying process succeeded in lowering the moisture to 7.2% for barley brewers grain and 5.4% for rye+barley brewers grain. The latter product proved to be more stable. Recipes for cake, cookies, and focaccia were developed using 50% rye brewers grain to replace the white flour the original recipe called for. The temperature, time, and baking method were optimized in a number of tests. In an initial sensory test, the products containing rye+barley brewers grain were assessed by 34 tasters. The cake, cookies, and focaccia were evaluated for flavor, texture, taste, and overall satisfaction; these parameters were measured on the basis of a seven-point hedonic scale (from „very good,“ to „very bad“). The results of the first trial showed that 66% of the tasters found the cake to taste „very good“ to „moderately good“ (Fig. 2), while the corresponding values for the cookies was 47% and for the focaccia 52%. None of the tasters reported unpleasant flavors in the products. This study was carried out in the framework of the „Brewing in Circle: Design and Implementation of the Recycling Process of Functional Byproducts of South Tyrolean Craft Beer (CirBeer)“ project funded by the Autonomous Province of Bozen / South Tyrol - Dept. for Innovation, Research, and University.
