Brewing with Whole Wheat Bread to Produce Different Beer Styles.

Beer is one of the most widely consumed alcoholic beverages and is rich in nutrients. Meanwhile, bread waste is a major contributor to global food waste. This study investigated substituting up to 50% of malt with whole wheat bread in American lager, Indian pale ale, and Bavarian weiss ale to reduce bread waste and enhance beer's nutritional profile. The study assessed physicochemical properties, bioactive compounds, and volatile profiles of bread-based beers versus traditional malt-based brews. Results showed that bread beers maintained key properties while increasing bioactive compounds, especially in Bavarian weiss, which had higher total polyphenol content (1.04 mg GAE mL compared to 0.507 mg GAE mL). Antioxidant activity in weiss beer also increased (2.007-2.057 μMol DPPH mL relative to 0.68-1.75 μMol DPPH mL in 100% malt weiss). PCA analysis highlighted a distinct bioactive profile in bread beers, with elevated phenylethyl alcohol and ethyl octanoate. Substituting malt with bread was feasible, producing beers of comparable quality and potential health benefits. These findings support bread as a sustainable, cost-effective malt alternative, reducing waste and enhancing beer within a circular economy framework.