Researchers in Singapore recycle brewing waste into yeast

Researchers at Nanyang Technological University (NTU) have developed a technique that promises to turn 85% of the waste produced in the process of beer brewing into yeast nutrients for more brewing.

Professor William Chen and PhD student Sachindra Cooray demonstrating the key parts of the beer waste conversion (from right): the brewer’s spent beer grains, the fermented spent beer grains, the liquid nutrient used to grow yeast, and the final beer. Photo credit: Nanyang Technological University

According to a report by the Strait Times, the researchers led by professor William Chen claimed they can add food-grade microorganisms to the used grains to produce a substance for yeast to kick-start brewing again.

The technique, if effective, could reduce 85% of the waste in brewing and save costs for brewers as well.

According to the report, every five litres of beer produced creates one kg of spent grain, which is usually used as compost or animal feed.

But the NTU researchers said they can turn the by-product into a liquid nutrient for yeast.

According to the team, the key is to break down plant fibres called lignin left behind after fermentation, and turn them into liquid that could be easily digested by yeast.

In addition, compared with commercial liquid yeast, which normally costs about US$30 a litre, the liquid nutrient produced by the NTU will be 20% cheaper, said the professor.

The new finding has already attracted interests from several international beverage companies including Singapore’s Asia Pacific Breweries (APB).

Over 193 billion litres of beer are produced worldwide each year, creating about 39 million tonnes of spent grain.