Brewer's spent grain (BSG) or draff is a

food waste The causes of food going uneaten are numerous and occur throughout the food system, during food production, production, food processing, processing, Food distribution, distribution, Grocery store, retail and food service sales, and Social clas ...

that is a byproduct of the

brewing industry Beer is an alcoholic beverage produced by the brewing and fermentation of starches from cereal grain—most commonly malted barley, although wheat, maize (corn), rice, and oats are also used. The grain is mashed to convert starch in the gr ...

that makes up 85 percent of brewing waste. BSG is obtained as a mostly solid residue after wort production in the brewing process. The product is initially wet, with a short shelf-life, but can be dried and processed in various ways to preserve it. Because spent grain is widely available wherever beer is consumed and is frequently available at a low cost, many potential uses for this waste have been suggested and studied as a means of reducing its environmental impact, such as use as a

food additive Food additives are substances added to food to preserve flavor or enhance taste, appearance, or other sensory qualities. Some additives, such as vinegar ( pickling), salt ( salting), smoke ( smoking) and sugar ( crystallization), have been used f ...

animal feed Animal feed is food given to domestic animals, especially livestock, in the course of animal husbandry. There are two basic types: fodder and forage. Used alone, the word ''feed'' more often refers to fodder. Animal feed is an important input ...

fertilizer A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Man ...

or paper.

Composition

The majority of BSG is composed of

barley Barley (), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains; it was domesticated in the Fertile Crescent around 9000 BC, giving it nonshattering spikele ...

malt Malt is any cereal grain that has been made to germinate by soaking in water and then stopped from germinating further by drying with hot air, a process known as "malting". Malted grain is used to make beer, whisky, malted milk, malt vinegar, ...

grain husks in combination with parts of the pericarp and seed coat layers of the barley. Though the composition of BSG can vary, depending on the type of barley used, the way it was grown, and other factors, BSG is usually rich in

cellulose Cellulose is an organic compound with the chemical formula, formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of glycosidic bond, β(1→4) linked glucose, D-glucose units. Cellulose is an important s ...

hemicellulose A hemicellulose (also known as polyose) is one of a number of heteropolymers (matrix polysaccharides), such as arabinoxylans, present along with cellulose in almost all embryophyte, terrestrial plant cell walls. Cellulose is crystalline, strong, an ...

lignin Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidit ...

, and

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

. BSG is also naturally high in

fiber Fiber (spelled fibre in British English; from ) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often inco ...

, making it of great interest as a food additive, replacing low-fiber ingredients.

Food additive

The high protein and fiber content of BSG makes it an obvious target to add to human foods. BSG can be ground and then sifted into a powder that can increase fiber and protein content while decreasing caloric content, possibly replacing flour in baked goods and other foods, such as breadsticks, cookies, and even

hot dog A hot dog is a grilled, steamed, or boiled sausage served in the slit of a partially sliced bun. The term ''hot dog'' can also refer to the sausage itself. The sausage used is a wiener ( Vienna sausage) or a frankfurter ( Frankfurter Würs ...

s. Some breweries that also operate restaurants re-use their BSG in recipes, such as in pizza crust. Grainstone is an Australian based company that has developed a world leading modular energy efficient process to convert BSG to a premium specialty flour and a process to produce

nutraceutical Nutraceutical is a terminology evolved scientifically & also through marketing which is used to imply a pharmaceutical effect from plant extracts, compounds, food products which have efficacy and therapeutic influence on clinical outcomes and patien ...

s; including protein isolate, soluble dietary fibre and antioxident.

Livestock feed

The low cost and high availability of BSG has led to its use as

livestock feed Fodder (), also called provender (), is any agriculture, agricultural foodstuff used specifically to feed domesticated livestock, such as cattle, domestic rabbit, rabbits, sheep, horses, chickens and pigs. "Fodder" refers particularly to food ...

. BSG can be fed to livestock immediate in its wet stage or once processed and dried. The high protein content in BSG offers a wide variety of amino acids essential in the diet of livestock. In fact, supplementing BSG in cow diets may increase milk yield, milk total solids content, and milk fat yield, when compared to maize.

Fertilizer

BSG may be an effective, affordable soil amendment for agricultural purposes. Its high protein content translates to high nitrogen availability in soils, which could be ideal for many common crops such as beets,

spinach Spinach (''Spinacia oleracea'') is a leafy green flowering plant native to Central Asia, Central and Western Asia. It is of the order Caryophyllales, family Amaranthaceae, subfamily Chenopodioideae. Its leaves are a common vegetable consumed eit ...

kale Kale (), also called leaf cabbage, belongs to a group of cabbage (''Brassica oleracea'') cultivars primarily grown for their Leaf vegetable, edible leaves; it has also been used as an ornamental plant. Its multiple different cultivars vary quite ...

, and

onion An onion (''Allium cepa'' , from Latin ), also known as the bulb onion or common onion, is a vegetable that is the most widely cultivated species of the genus '' Allium''. The shallot is a botanical variety of the onion which was classifie ...

s. In combination with

compost Compost is a mixture of ingredients used as plant fertilizer and to improve soil's physical, chemical, and biological properties. It is commonly prepared by Decomposition, decomposing plant and food waste, recycling organic materials, and man ...

, BSG may improve germination rate and the availability of organic matter in soil. Studies have shown that BSG in addition to compost has a stronger, positive effect on germination than compost alone. An additional study has shown that the inclusion of BSG in soil is more effective at sodic soil reclamation and corn seed germination than gypsum, which is traditionally used in sodic soils.

Paper

BSG can be used to making recycled paper. It's called Craft Beer Paper or Beer Paper. Because of BSG, the paper shows subtle beer hue. It has been made into postcards, coasters, gift boxes, and A4 and B5-sized beer paper sheets that can be printed just like regular white printing paper. Beer Paper had obtained FSC® certification.

Ceramics

Brewery's spent grains could be recycled through their incorporation in a traditional ceramic paste used in the manufacture of common bricks. This incorporation affects the mechanical strength, porosity, and thermal conductivity of the ceramic material.

Mushroom Substrate

Both completely dried BSG, and fresh BSG (with an average ~79% water content) have successfully been utilized in small home and small commercial mushroom substrate production. Additional, alternative sources of lignin from coffee, soft wood pine/douglas fir sawdust, and harder wood sawdust (in pellet form as well) have been shown to help in mushroom production block manufacturing. These industrial byproducts may offer less expensive material costs in block production as well as a higher level of waste reuse in mushroom production. The highest average yield (there are many growing factors involved) was found to be with a ratio of fuel pellet : BSG : hot tap water of 450 : 725 : 825 (all measured in grams in the study per each T3 filter patch bag utilized for the production blocks), with testing for field capacity being a final assessment of fine tuning these ratios (to get a 'feel' for proper hydration, by experienced block producers, via hand compression testing of a hydrated and mixed batch of substrate.)

References

{{Authority control Biological waste Brewing