Nearly 4 000 years after it was first created, beer is still made using four primary ingredients: water, malted barley, hops and yeast. However, modern beer-brewing processes create a number of by-products, each of which is put to efficient secondary use.
Note that we refer to these as by-products rather than waste products as they are repurposed in agriculture, as animal feed, fuel sources and food additives, and in the pharmaceutical industry.
“This practice is in keeping with South African Breweries’ objective of ensuring that nothing goes to waste,” says World of Beer general manager Tony Rubin.
For every 100 litres of beer produced, around 11kg of by-product is generated. Of that, 10.2kg comprises spent grain, while the remainder is made up of yeast and malt dust.
Wet spent grain that comes out of the brewing process is high in nitrogen and fibre, protein, carbohydrates and omega oils, making it ideal for use as livestock feed. It is also repurposed for use in fertiliser, compost, biogas, boiler fuel and high-fibre food snacks. The malting process produces malt rootlets, also used in animal feed, along with feed barley.
All the wet by-products have a high moisture content, which makes them biologically unstable. This means there has to be a quick turnaround time to ensure that the products are reused within 24 hours.
The pharmaceutical industry puts barley rootlets and probiotics to good use, while spent grain is repurposed in the production of xylitol (an alternative to sugar), resins and polymers (a molecular substance made from many similar units bonded together).
Surplus yeast is used in pet food and horse feed, as a growth medium for vitamins, bacteria and amino acids, and is incorporated into nutritional supplements, alcoholic beverages and yeast extract. Wet yeast is used as a food source by pig farms.
Sweepings and any spillage that accumulate where raw materials are offloaded are collected and bagged, to be used as part of the livestock feed for pigs and cattle. Malt dust, in particular, forms an important part of cattle feed due to its high nutritional value.
In keeping with South African Breweries’ objective of ensuring that nothing goes to waste, even the coal used to fire up the boilers is collected. In its ash form, this is incorporated in the manufacture of grout, concrete, bricks and roofing materials.
During 2016, South African Breweries South Africa – comprising breweries in Rosslyn, Alrode, Chamdor, Polokwane, Ibhayi, Prospecton and Newlands – produced a total organic volume of 325 000 tons.
“We like to think of our brewing process as a win-win; we get the beer, while multiple other sectors put our by-products to good use,” says Rubin.