Making a profit from brewery waste streams

Tuesday 06 Dec 16


Preben Bøje Hansen
Food technologist
National Food Institute
+45 45 25 75 17

Breweries can secure further earnings with a newly developed compact filter, which gently and economically extracts fiber, protein, sugar, antioxidants and vitamins from their by-product spent grain. The machine is based on inventions developed at DTU Brewery, which is housed at the National Food Institute, Technical University of Denmark. The DTU spin-out DACOFI has acquired a license to four patents that protect the technology. 

In the quest to make the DTU Brewery energy neutral, its employees have developed a compact filter that can be used to utilize nutrients in the by-product spent grain in an economically viable way.

Spent grain contains both lots of fibre and approximately 6% of the amount of protein present in the raw materials – protein which, if extracted, can be used in the production of e.g. fortified foods.

Economically viable technology

The idea of utilizing spent grain in food production is not new. However, until now it has not been economically viable to dry the spent grain.

The newly developed technology makes it possible to gently and inexpensively separate the spent grain via filtration and simultaneous compaction into a liquid fraction and a solid substance. Subsequently, the solid substance is dried or acidified while the liquid fraction is pasteurized or acidified in order to obtain a longer shelf life, or it is used in the production of light beer or directly in food production. 

Once the spent grain has been dried or acidified, the fibrous substance can e.g. be used in bread to improve fibre content. Sediment in the liquid which contains proteins, sugar and antioxidants can be separated in a centrifuge and then be used to enrich e.g. dairy products and protein drinks. The price of dried spent grain is about 1 US dollar per kilo, while the sediment can fetch about 6 US dollars per kilo.

DACOFI is currently working to identify ways to increase the value of both the liquid and the solid parts.

Scalable machine

The compact filter is scalable up to 30 cubic metres per hour. This means that companies of different size - from microbreweries to the biggest breweries - can utilize the technology.

A Swedish business has already purchased a license for the technology and is now selling the compact filter to companies that want to utilize the by-product potato pulp, which is generated during potato flour production.

DACOFI is constantly trying to develop the machine so that it can be used for other fiber-containing substances, such as fruit pressing. Tests have so far shown that the machine can remove 80% of the juice from a pear, but DACOFI expects that the result can be improved with some adjustments to the machinery.

Read more

Find out more about the rotary dewatering press on DACOFI’s website. DACOFI has received InnoBooster funding from Innovation Fund Denmark to help develop the machine.