The researchers wanted to see how adding bilberries to beer at different stages affects its taste and composition. They used a brewing system to make beer with bilberries added at the start and after a week of maturation. Adding bilberries increased the levels of certain healthy compounds like phenolic acids and flavonoids in the beer. The bilberry beers had more chlorogenic and neochlorogenic acids, rutin, and catechin. They also found that adding bilberries reduced the protein content in the beer by a lot. Overall, the study showed that adding bilberries to beer can change its flavor and make it healthier.