Brewing Mainly from Stale Bread: A Pale Ale Case Study

Abstract

Contemporary environmental concerns have led to the prioritization of sustainable production and material circularity, no matter what the industrial field of activity. Bread waste is a major element of overall food waste since, worldwide, bread remains a widespread staple food. A considerable proportion of bread consumption is of fresh, baked bread, consumed daily, generating substantial amounts of stale bread. Therefore, efforts to reintroduce this waste into the food value chain can make a significant contribution to reaching zero food waste, which is a major target in European countries. Possible ways to produce new raw materials through starch enzymatic hydrolysis include brewing, which is an activity in which incorporating stale bread is of great interest. Mashing parameters in brewing processing are the main focus of this study, primarily the time and temperature required to acquire optimal enzymatic activity for starch-efficient hydrolysis. Extending the mashing time to 290 min, within a temperature range of 45–75 °C, allowed us to replace 50% of the required malt with stale bread, thus obtaining a successful pale ale beer. The incorporation of stale bread in a 50:50 ratio did not affect the overall character of the beer, although the alcohol levels stood around 2% below a standard beer’s average level. Depending on the brewer’s final goal, this lighter kind of beer may be well-aligned with new consumer trends supporting more sustainable and lower-alcohol beverages.