Environmentally Conscious Brewer By-Product Disposal Methods

Realizing the importance of environmentally friendly waste management is crucial in every industry.  We have a limited amount of resources, and, combine with a growing population, the significance of sustainable use has become increasingly critical to society.

Different industries must form individualized practices that best suits the type of waste they produce.  The brewing process produces waste including spent grain, yeast, and hops or hot trub.  For large, industrial companies, research has been done on the most efficient way to sustain an environmentally conscious waste removal and use program.  For smaller, craft breweries, less information, and fewer options are available for waste disposal.

My interest in this topic comes from the use of spent distillers grains as animal feed.  Distillers’ grains contain high concentrations of sulfur, nitrogen, and fat, while providing minimal starch, which is difficult for most animals to digest.  This product is used as a source of fiber in the diet of goats, sheep, and cows, as well as a protein supplement for horses.  Unfortunately, there is little research on the long term effects of feeding these grains or how distillers dispose of these waste products in the United States and other countries. 

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One USDA research project, conducted in 2013, determined that E.coli bacteria were able to live longer in the feces of cows fed 40% and 70% distillers grains for over 28 days, as compared with cows consuming none.  This is likely due to the lower starch content of distillers grains, however, could also be attributed to the nitrogen, sulfur, or fat concentrations as well.  Another study performed at Lethbridge Research Station found that cows fed distillers grains produce decreased amounts of methane, but, higher amounts of nitrogen due to the increased concentration of nitrogen in the distillers’ grains.

This research article surveyed and analyzed the waste management procedures of ninety (90) craft brewers located in Britain.  For this studies purposes a craft brewery is defined as “a small, independent brewer who uses traditional production methods” (Kerby, 2017, 2).  Differences occur not only between large and small breweries, but, also between urban and rural craft brewers.  Urban brewers may dispose of waste via sewage, landfill, bio-recycling and anaerobic digester plants.  Rural companies are more likely to have a personal relationship with those using their by-products.

Spent grain makes up the largest portion of waste created by brewery production.  This by-product can be used for both animal feed and human consumption.  Spent grains have a high fiber and protein content, as well as nitrogen-containing nutrients, essential for life on earth.  These grains offer a low cost alternative to animal farms, who may otherwise have to spend time, energy, and money to produce or purchase traditional feed materials.  Spent grains can be composed, however, must be combine with other waste to do so.  Lastly, spent grains can be used in energy production through combustion or fermentation.  This is a promising option, as it uses sustainable reactants and produces by-products which can be used to power the community.

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Black – Batch capacity below 1000L

Red – Between 1000-2000L

Green – Greater than 2000L

Spent Grain Usage

Another waste product of craft brewer production is spent hops, usually removed before the fermentation process, but, can be added at any time.  These are not as efficient as animal feed, as they have a bitter taste which cows or horses are likely to reject, and provide 50% less energy than spent grain (Kerby, 2017).  The most common management practice for spent hops is to reuse them in fertilizers or compost them.  Unlike spent grains, spent hops can be stored efficiently for long periods of time and make up the smallest volume of waste produced, meaning they don’t take that much space to store.  The size of the brewer determined how often they had spent hops removed.  Small operations once a week, larger operations two to three times per week.  Disposing of spent hops does not typically cost the brewery, however, they rarely receive money for their spent hops.

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Black – Batch capacity below 1000L

Red – Between 1000-2000L

Green – Greater than 2000L

Spent Hop Usage

Spent yeast is the remaining waste product, which can be used as either animal or human feed supplement.  There are a variety of yeast spreads, such as marmite, sold, which can be produced using extracts of the spent yeast.  This by-product is a source of minerals, essential amino acids, and B-complex vitamins, all required elements of human and animal nutrition.  It is far less common to use spent yeast in animal feed, and sadly, the most common method of disposal is through sewage systems.  Larger companies are likely to incur higher cost for disposal of their spent yeast, while smaller operations must use the sewer, as they do not brew often or large enough quantities for other methods to be sustainable.

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Black – Batch capacity below 1000L

Red – Between 1000-2000L

Green – Greater than 2000L

Spent Yeast Usage

          This study had a small sample size, meaning another, larger study is in order to get a better scope of disposal methods and which are most utilized.  Other factors, such as where they get their unused materials and the efficiency of their production process should also be assessed for environmental sustainability.  Craft brewers have a variety of options when it comes to waste management, however, the method chosen depends of brewery size, which product they are trying to dispose of, and location.  Smaller breweries, especially rural ones, incurred less cost for waste disposal, as they produce less and, therefore, have a low quantity of by-products.  The larger the brewery becomes, the more likely they are to have expenses associated with the disposal of their waste.  It is vital that the managers of each brewery recognize the importance of green waste disposal, and design a program specifically for that company, keeping sustainability in mind. 

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Works Cited:

“An Overview of the Utilisation of Brewery By-Products as Generated by British Craft Breweries.” Clare Kerby and Frank Vriesekoop, 2017.

“Feeding Wet Distillers Grains Could Spike E. coli Levels.” Food Safety News, 2013.

“The environmental pros and cons of feeding dried distillers grains.” Alma Release, 2015.