Brewers Spent Grain: Economic and Circular Opportunity for the Spanish Agri-Food Sector

Spain generates 800,000 tonnes of brewers spent grain annually, a by-product with multiple profitable applications that is evolving from simple animal feed to an ingredient for human consumption, bioenergy and biomaterials. As the second largest beer producer in Europe after Germany, the country has a constant flow of this underutilized resource that can generate significant economic value. The Spanish brewing sector contributes €17.2 billion to national GDP and its commitment to the circular economy is transforming BSG into a strategic asset for breweries, livestock farmers and valorization companies.

Production and Economic Relevance of BSG in Spain and Europe

The Spanish brewing industry produced 41.29 million hectolitres in 2024, consolidating its position as the eighth largest producer worldwide. This activity generates approximately 700,000-800,000 tonnes of wet BSG annually, applying the technical ratio of 20-22 kg of BSG per hectolitre of beer produced. Large industrial breweries concentrate most of this production, distributing it among their multiple facilities nationwide.

At the European level, the EU produced 346.3 million hectolitres in 2023, generating more than 7 million tonnes of BSG annually. Germany leads with 84.9 million hectolitres, followed by Spain, Poland and the United Kingdom. This scale has fostered a market valued at USD 509.25 million (2024) with a projection of USD 639.12 million by 2032.

The Spanish brewing sector generates more than 540,000 direct and indirect jobs, collects €6.5 billion in annual taxes and maintains a verifiable commitment to sustainability. 98.8% of brewing waste is currently valorized, with BSG representing 85% of total by-products generated.

Technical Composition and Nutritional Value of Brewers Spent Grain

Brewers spent grain has an exceptional nutritional composition that justifies its use in multiple applications. On a dry matter basis, it contains 24-26% crude protein, 46-53% neutral detergent fiber (NDF) and 7-8% ether extract. Its mineral profile stands out with 0.50-0.55% phosphorus and 0.20-0.26% calcium, although this inverted Ca:P ratio requires calcium supplementation in animal diets.

The differences between wet and dried BSG are crucial for commercialization. Wet BSG contains 75-80% moisture, barely 20-25% dry matter, and has a critical shelf life of 3-7 days in warm climates due to high microbial activity. In contrast, dried BSG reduces moisture to less than 10%, allowing storage for more than 6 months and facilitating long-distance transport, although it requires significant investment in drying infrastructure.

Compositional variability depends on the type of beer and production process. Industrial breweries achieve extraction efficiencies above 90%, leaving barely 2-3% residual starch in the BSG. Craft breweries, with less efficient processes, can generate BSG with up to 33% residual starch, significantly modifying its nutritional properties.

The bioactive compounds present in BSG add functional value: it contains 2,310 mg/kg of total phenolic acids (mainly ferulic and p-coumaric with antioxidant properties), beta-glucans with prebiotic activity, and B-group vitamins. Its protein profile includes 30% essential amino acids, although lysine is limiting. Rumen degradability of 41-49% and bypass protein of 51-59% make it an excellent ingredient for high-production ruminants.

Current Prices of Brewers Spent Grain in the Spanish and European Market

The price of wet BSG in Spain ranges from free to €83/tonne depending on specific conditions. The Spanish market operates predominantly under a circular economy model where breweries deliver BSG to local farmers and livestock producers at no cost or for a symbolic price, with the latter only assuming transport costs. When monetized directly, the typical range is €35-75/tonne, calculated based on its protein equivalent compared to soybean meal.

For dried or dehydrated BSG, prices are between €150-250/tonne, a multiple of 4-5 times higher than wet due to the energy cost of industrial drying. This price is competitive compared to other protein sources for animal feed.

In other European countries the model is similar. Germany maintains prices of €35-75/tonne for wet product. Transport typically adds USD 16 per tonne every 8 kilometres, showing how logistics becomes a crucial limiting factor.

Price-determining factors include location (transport adds €15-20/tonne per 8-10 km), negotiated volume, moisture level and preservation method. Ensiling adds €5-10/tonne but extends preservation to 6-12 months. Beer production remains relatively constant throughout the year, minimizing the impact of seasonality.

Compared to similar by-products, BSG offers excellent value for money. Wet sugar beet pulp has comparable prices (€40-80/tonne) but with lower protein content (10-12% vs 24-26%). Corn DDGS, with 27-35% protein, costs €100-150+/tonne. The Spanish market has experienced a moderate upward trend since 2023, when the conventional feed price crisis boosted demand for economical alternatives.

Applications of Brewers Spent Grain and Their Economic Valuation

Animal feed absorbs 70% of BSG generated in Spain (560,000 tonnes annually). In dairy cattle, the optimal inclusion is 15-25% of total dry matter, equivalent to 10-15 kg daily of wet product per cow, demonstrating increases in milk production, higher fat and solids percentage. Large breweries maintain alliances with dairy cooperatives delivering thousands of tonnes annually that feed hundreds of cows with verified results. For beef cattle, inclusions of 15-30% achieve weight gains comparable to corn-based diets. Sheep tolerate up to 60% without affecting digestibility, with 38% savings in supplements. Swine accept 17-25% in dried format, while poultry requires enzymes for 10-20% inclusions. Aquaculture emerges as a promising application: European projects validated 10-20% inclusions in sea bream and trout with yields superior to conventional diets.

Compost production represents 10% of Spanish BSG (80,000 tonnes). Its optimal C/N ratio facilitates composting in 6-7 months producing high-quality organic amendment. Innovative applications include peat substitute in soilless substrates, with results superior to gypsum in recovering sodic soils.

Bioenergy applications capture another 10% (80,000 tonnes). Methanogenic potential reaches 553-578 mL of methane per gram through pretreatments, requiring co-digestion with manure. Spanish breweries operate biomethanization plants that cover up to 50% of their electricity demand. As solid biomass, it offers a calorific value of 16.9 kJ/g for energy pellet production.

Human food applications represent less than 5% but show the highest growth potential. Breweries develop edible coffee stirrers, protein-rich flour (64.9-70% fiber), healthy snacks (cookies, bars), pasta with BSG (14% protein, 11% fiber) and edible cutlery. These applications multiply economic value by 1,000 compared to animal use, although they require R&D investment and Food Code compliance.

Edible mushroom cultivation utilizes cellulose achieving colonization 2-3 times faster than traditional substrates (5 days vs 10-15). Profitability is attractive: from 2.3 kg of spawn, up to 27 kg of fresh mushrooms valued at USD 480 are obtained, with premium markets at USD 8/pound.

Bioplastics and biomaterials attract European funding. Projects transform BSG into polyhydroxyalkanoates (PHAs) for agricultural films, textiles and packaging. European pilot facilities produce food containers, coasters and biodegradable trays at semi-industrial scale (150-300 kg/hour).

Logistics, Preservation and Marketing Models for BSG

Economically viable distances constitute the main constraint for wet BSG. With 75-80% moisture, transport cost increases €15-20/tonne per 8-10 km. At 50 km, transport can reach €75-100/tonne, equaling product value. Viability is limited to a 60 km radius from the brewery. Industrial drying solves this limitation but requires an investment of €80-150/tonne.

Preservation systems present different profiles. Fresh BSG offers maximum palatability but 3-5 day shelf life. Refrigeration at 4°C extends life beyond 16 days with continuous energy cost. Ensiling allows 6-month preservation adding only €5-10/tonne. Drying generates stable product for more than 6 months but with high energy cost.

There are specialized distributors with ensiling infrastructure exceeding 8,000 tonnes guaranteeing year-round supply. Large breweries establish direct contracts with farms and cooperatives distributing tens of thousands of tonnes annually.

Three marketing models coexist: The free model (60-70% of market) implies the farmer collects directly assuming only transport within 20-60 km radius. The logistics cost model (20-25%) establishes that the farmer pays only transport (€30-80/tonne). The profit sale model (10-15%) involves distributors who purchase, process through ensiling or drying, and resell with margins of €80-250/tonne.

Typical contracts are long-term B2B agreements specifying annual volume, collection frequency (recommended every 5 days), transport responsibility and price. Emerging digital platforms for industrial symbiosis facilitate connections between supply and demand.

Spanish and European Regulatory Framework Applicable to Brewers Spent Grain

BSG of exclusively plant origin does NOT fall under SANDACH scope (Regulation EC 1069/2009). Feed regulations apply: Regulation (EC) 767/2009 on hygiene and safety, and Regulation (EU) 68/2013 that includes BSG in the Catalogue of Feed Materials with mandatory declarations of moisture and crude protein.

Classification as by-product vs waste is crucial. Order APM/189/2018 establishes that agri-food waste destined for animal feed is considered by-products when they comply with: being on authorized lists, complying with Regulation 767/2009, complying with Regulation (EC) 183/2005, and coming from registered establishments. As a by-product it can be marketed without waste management restrictions (Law 7/2022).

Health requirements for animal feed include: registration in the General Register of Animal Feed Establishments (Royal Decree 629/2019), HACCP system, periodic bromatological analyses, complete traceability through operation and batch records, and official controls according to Regulation (EC) 882/2004. Labeling must indicate moisture and crude protein.

Traceability obligations according to Regulation (EC) 178/2002 include: product description, volume, origin, destination, transaction date, chronological archive, batch records, documented controls and rapid withdrawal system in health alerts.

Relevant certifications add value: ISO 22000:2018 (food safety), ISO 22005:2007 (traceability), GMP+ Feed Certification, BRC Food, IFS Food, and organic certification (Regulation EU 2018/848) for organic beer BSG.

Documented Success Cases in Spain and Europe

Large Spanish breweries lead innovation in valorization with rates exceeding 99% by-product utilization. Several have developed alliances with foodtech startups to market innovative products such as edible coffee stirrers made with BSG flour in the horeca channel since 2022. These startups have achieved funding rounds exceeding €500,000 and growing revenues. European projects like CHEERS (Horizon Europe 2022-2026) develop conversion of brewing waste into five industrial bioproducts with a 45% carbon footprint reduction target.

Verified circular economy models include alliances between large breweries and dairy cooperatives supplying thousands of tonnes annually to feed hundreds of cows, achieving mutual benefit. Biomethanization plants operational for over 20 years produce up to 50% of electricity consumed in facilities, demonstrating long-term technical and economic viability.

B Corp certified breweries have achieved Zero Waste certification through 100% by-product valorization. Complete circularity projects transform BSG into animal feed whose milk returns to produce specialty beers. Food innovation programs develop healthy snacks with university participation. Alliances with poultry farms produce eggs with environmental footprint certification through BSG feeding.

Hospitality sector initiatives implemented by large breweries include hundreds of sustainability-certified member establishments, with thousands of actions avoiding hundreds of tonnes of CO2 and saving millions of litres of water.

The sector as a whole has achieved ambitious certifications like "Zero Waste" with valorization rates exceeding 99.7%, reintroducing more than 200,000 tonnes annually of by-products. Several factories hold "Zero Emissions" facility titles.

Funded European projects include LIFE Brewery (2017-2021), which developed low-carbon dehydration technology and new validated ingredients for aquaculture with no differences vs commercial feeds, reducing dependence on fishmeal. Ingredients demonstrated properties for human consumption (prebiotics, antimicrobials, antioxidants).

Craft breweries replicate the circular model at local scale marketing organic BSG flour, pasta with BSG and bakery products, closing the production cycle. They allocate their BSG to local livestock and bioplastics R&D projects, contributing to rural revitalization.

Specialized distribution companies with over 45 years in the sector demonstrate the viability of the professional logistics model with quality certifications, guaranteeing nationwide supply year-round through ensiling infrastructure exceeding 8,000 tonnes.

Conclusions and Commercial Opportunities

Brewers spent grain has evolved from a problematic waste to a strategic resource in the Spanish and European circular economy. With 800,000 tonnes annually in Spain valued between free and €83/tonne in wet format, or €150-250/tonne dried, there is a consolidated market with growth potential in high-value applications. Animal feed absorbs the current 70% providing immediate solution but limiting valorization potential.

Emerging applications in human food multiply value by 1,000, as demonstrated by sector startups and food innovation programs. Bioenergy offers verified partial self-sufficiency after decades of operation. Bioplastics attract European funding with multi-million potential markets. Edible mushroom cultivation combines immediate profitability with low entry cost.

For breweries, it is recommended to diversify destinations: maintain local alliances with farmers within 60 km radius, explore drying investment to expand market, participate in European R&D consortia, and develop alliances with startups through open innovation.

For livestock farmers, free or low-cost wet BSG (€0-50/tonne) represents 20-30% savings in feed with verified productivity improvement, especially in dairy cattle with 20-25% inclusions.

For valorization companies, opportunities include specialized distribution with ensiling, premium mushroom cultivation (USD 8/pound market), flour production for human consumption (1,000x factor vs animal), and bioplastics development with European funding.

The regulatory framework facilitates this transition: Order APM/189/2018 classifies BSG as a by-product when it meets basic requirements, avoiding waste management burdens. With 98.8% current valorization, the path to 100% requires replicating documented models from the Spanish brewing sector, definitively transforming BSG into a strategic asset of the national bioeconomy. Specialized platforms for agricultural by-product marketing facilitate this efficient connection between generators and buyers, optimizing logistics and maximizing utilization of this valuable resource.