Edgy burger business BurgerFuel has branched out to create a craft beer.

Made from rescued surplus bread from supermarkets, its beer is made as part of a partnership with Citizen, which routinely rescues and upcycles unsold fresh supermarket bread to create craft beer.

From today two variations of BurgerFuel's beer - named LagerFuel and LagerFuel Light - will go on sale online at Citizen.co.nz and at BurgerFuel Napier.

The release of the branded BurgerFuel beer marks 27 years in business for the gourmet burger chain, the company said.

The beer will be a limited edition for now, available while stocks last. However, BurgerFuel hopes the concept will be well-received and it will be able to continue to tap into the circular economy to reduce food waste.

More than 29 million loaves go to waste in New Zealand every year, which is why BurgerFuel had decided to team up with Citizen to address "needless food waste", the company said.

LagerFuel and LagerFuel Light are brewed in partnership with the country's only B-Corp brewery, Sawmill Brewery, which uses the fermented sugars of wasted bread in the brewing process.

BurgerFuel said the result is a crisp, refreshing lager that rescues one slice of bread per can.

Long-term, BurgerFuel wants to use the high-quality, nutritious spent-grain flour by-product from the LagerFuel and LagerFuel Light brewing process and upcycle it again to bake wholemeal buns for its restaurants.

"We're hoping that people will love the beer, resonate with the purpose, and help us sell through our first batch, meaning there's a real potential for selling into liquor retail and supermarkets," said BurgerFuel head of brand and marketing Nikki Soons. "Then we could see not only a great-tasting, positive impact craft beer on shelf, but spent grain flour BurgerFuel buns on the 2023 menu, completing the circularity objective of the initiative."

BurgerFuel food and menu development manager Chris Mills said repurposing the grain had environmental and nutritional benefits.

"A lot of work has gone into the development of our buns over the years.

"There's no added sugar in our recipe, that sweetness is achieved with pumpkin and potato flour. And by incorporating the spent grain, we can reduce the amount of refined white flour required in each bun by 4 per cent, which enhances the flavour, but also with the added environmental benefit."

BurgerFuel launched its first restaurant in Ponsonby in 1995 and today operates 60 stores across the country.

Recycled food and beverage business Citizen was co-founded by restaurateur Ben Bayly in 2019 using rescued bread from supermarkets to make craft beer and sourdough bread.

As part of its process, it takes bread sold in the supermarket close to its expiry, extracting the starch and replacing malt to make beer. From the brewing process, leftover bread-brew mash is turned into spent-grain flour to make its bread.

The operation has recently expanded to create a range of sauces made from recycled tomato and mushrooms, and a vegan mayo, made from upcycled chickpea water.