Study gives breweries a new way to decide how to use spent grain

A new study in the journal Waste Management says breweries can make more informed decisions about how to use brewer’s spent grain, one of the beer industry’s largest byproducts, by weighing profit and environmental impact at the same time.

Brewer’s spent grain, often called BSG, is the wet barley residue left after mashing and lautering in beer production. It is produced in large volumes around the world and spoils quickly because of its high moisture content. That makes it both a waste problem and a business opportunity for breweries and food processors looking for ways to turn it into animal feed, compost, energy or higher-value ingredients.

The paper, titled “Pathway development for brewer’s spent grain valorization using multi-objective optimization,” presents a model designed to help companies compare different uses for spent grain under two main goals: improving earnings before interest and taxes, or EBIT, and reducing carbon footprint. The work was published by Elsevier in Waste Management and focuses on how breweries can choose among competing pathways instead of treating waste handling as a simple disposal issue.

According to the study summary, the model found that animal feed was the most profitable route among the options examined, while composting delivered the lowest environmental impact. That result points to a familiar trade-off in industrial food systems: the option that brings in the most money is not always the one that cuts emissions the most.

The research matters because spent grain is generated at nearly every brewery, from large industrial plants to smaller regional producers. Beer production creates substantial side streams, and spent grain accounts for most of that volume. In many cases it is sold cheaply, given away locally or hauled off at added cost. A framework that compares financial returns with climate effects could help breweries decide whether to invest in drying equipment, transport systems, processing partnerships or new product lines.

The study arrives as breweries face pressure on several fronts. Energy costs remain volatile. Waste disposal fees can be significant. Investors and regulators are paying closer attention to emissions and resource use. At the same time, brewers are looking for ways to improve margins in a competitive market where beer demand has become less predictable in some regions.

Using multi-objective optimization, the researchers built a decision framework rather than promoting a single universal answer. That approach is important because the best use for spent grain can depend on local conditions such as transport distance, energy prices, access to livestock markets, compost demand and processing infrastructure. A brewery near farms may find feed sales practical and profitable. Another operation in an urban area may see better results from composting or from sending material into another industrial process.

The paper’s central contribution is not simply that feed can earn more money or that compost can lower emissions. It is that breweries can evaluate those outcomes together and identify where trade-offs are acceptable. For managers deciding on capital spending, that kind of model can be more useful than a narrow analysis based only on disposal cost or only on sustainability targets.

Spent grain has drawn growing interest from researchers and food companies because it still contains fiber, protein and other compounds with potential value. Some projects have explored its use in baked goods, snacks, fermentation inputs, biomaterials and bioenergy. But many of those pathways require extra processing, stable supply chains and buyers willing to pay enough to justify investment. The new study adds to that discussion by framing valorization as a strategic choice shaped by both economics and emissions.

For breweries, especially medium-size producers that may not have large research budgets, such tools could help reduce uncertainty before committing money to new equipment or outside contracts. If a company knows that one pathway improves EBIT but raises its carbon footprint, while another does the reverse, it can make a clearer decision based on its own priorities, regulatory exposure and customer expectations.

The findings also have implications beyond brewing. Food and beverage manufacturers across sectors are trying to extract more value from byproducts while cutting waste. Models like this one could be adapted for other residues from distilling, winemaking, dairy processing or grain milling, where companies face similar questions about whether to prioritize revenue, emissions reductions or a balance of both.

The study underscores a broader shift in how waste is viewed in the beverage industry. Instead of treating byproducts as an unavoidable cost, producers increasingly see them as part of operational strategy. In that context, brewer’s spent grain is not just leftover material from making beer. It is a test case for how breweries can connect environmental goals with financial performance when deciding what happens after the mash tun is emptied.