Beer production and ethanol – sustainable alternatives for bread waste

In an earlier article, researchers at the University of Borås and the Swedish University of Agricultural Sciences (SLU) presented how much bread waste we have in Sweden: 80,000 tonnes are thrown away each year and 70% of that bread waste comes from households and retailers. Now the researchers have investigated different ways to process bread waste in order to determine the most sustainable alternatives.

"As much of the bread is collected by bakeries separately from other waste fractions, there are several things we can do with it. For example, we can produce ethanol or animal feed,” says Pedro Brancoli, doctoral student in Resource Recovery at the University of Borås and lead author of the new study.

Not using bread waste is not only a waste of the product itself, but also of the resources invested in its production, transport, and storage. But is this a sustainable path to take, to instead produce ethanol and feed from bread waste?

"In the new study, we have investigated different ways to process bread waste. There has previously been no evidence that such approaches are better than those currently in use in Sweden, i.e. producing biogas or burning the bread," says Pedro Brancoli.

However, this study’s results show that alternative ways of processing the surplus of bread, such as through the production of ethanol, animal feed, and beer, are solutions that have greater environmental benefits.

The study also shows that transport routes are important when assessing the benefits of alternative ways of handling bread waste. This highlights the importance of infrastructure diversification and the use of local solutions to process bread surpluses.

Paths for both the consumer and the retailer

"If we compare bread with beef, for example, beef has more than 50 times the environmental impact per kilogram. The focus should therefore be on how we can reduce waste, and not necessarily on the consumption of bread, as bread is already an environmentally friendly food, when eaten," says Pedro Brancoli.

On the consumer side, research has shown that bread is one of the products that goes to waste in households; the main reason is that bread moulds.

“Strategies to prevent this should relate to adapting bread purchases to consumption and finding ways to extend shelf life. This can be done by freezing or reusing bread; for example, as breadcrumbs and in dishes that our parents and grandparents have used for many years.”

“Since part of the retailers' current business model increases the risk of waste production, it may be necessary to change it. This can mean that retailers become responsible for their orders and for unsold products, as this is the case for most other products sold in retail,” says Pedro Brancoli.

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Environmental impacts of waste management and valorisation pathways for surplus bread in Sweden