"We're helping Kiwis save the world by doing what they enjoy best - drinking beer," said DB spokesman Sean O'Donnell.
Since 2007, Gull has offered a biofuel containing 10 per cent ethanol formulated using New Zealand whey - a dairy industry by-product - and Brazilian sugarcane.
An initial batch of 300,000 litres of Brewtroleum has been formulated using 30,000 litres of ethanol, which was extracted from more than 58,000 litres of leftover yeast slurry that would otherwise be distributed as stock feed, or discarded. Mr O'Donnell expected the first lot of fuel to last about six weeks, but he'd like to see it become a long-term offering.
"It's a case of testing consumer demand and assessing the feasibility of ongoing production and logistics."
New Zealand's Energy Efficiency and Conservation Authority website says using biofuels helps reduce emissions of carbon dioxide - the main greenhouse gas contributing to global climate change - from cars.
The Automobile Association says drivers using 30 litres of biofuel a week would save more than 250kg of carbon dioxide emissions every year.
In comparison, the emissions for a person flying from Auckland to Sydney are about 237kg, according to Air New Zealand's website.