Beer is one of the most consumed drinks around the world. Beer production, with a significant consumption of energy, mostly of fossil origin, generates large amounts of waste, raising some concerns due to its environmental impact. Many organic wastes can be converted into value-added products. In particular, the cereal bagasse resulting from the beer production process, Brewer’s Spent Grain (BSG), is proposed as a substrate in anaerobic digestion (AD) to produce biogas and biomethane. The liquid and solid digestates resulting from this process can be used as biofertilizers. Alternatively, the biogas and the liquid portion of the digestate can be processed to obtain hydrogen through reforming and electrolysis, respectively, which can also be used to generate heat or electricity to meet the energy needs of the breweries themselves. Wastewater from the brewing process or from other productions neighboring the factory, such as from olive oil mills or cheese factories, can be co-processed by AD and serve as feed for electrolysis to produce hydrogen, contributing to the treatment and promotion of the circularity of water as a resource.