13 Nov 2013

Student's clean, modern umu could transform island cooking

5:28 pm on 13 November 2013

A Samoan engineering student in Dunedin in New Zealand has created a modern, clean-burning umu which could transform traditional island cooking.

The efficient log-burner type oven uses only one-quarter of the usual amount of wood, and does not produce harmful smoke or fumes.

The Otago Polytechnic student expects his idea to spread right across the Pacific, as Ian Telfer reports.

In a lean-to beside his South Dunedin church, John Eteuati is showing off his new umu.

"JOHN ETEUATI: Well, we've got this lid up top here made of stainless steel and I've got the rocks here. This is part of the traditional method."

It's those hot rocks which give the melting flavour to so much Pacific cooking. But the problem is heating those stones to hundreds of degrees to bake taro and fish and pork uses a lot of wood - about 60kg each time.

JOHN ETEUATI: The umu, as we call it in the islands, the Maori call it 'hangi'. We still burn a lot of wood, excessive fuel. WIth that type of cooking it produces a lot of harmful, excessive smoke and it's been years and years, even up till now the Pacific Islanders have been exposed to these harmful gases.

At the top of Mr Eteuati's oven there's a large steel base holding the cooking rocks with a barbecue-style lid closingover the food. But the real innovation is below, where a closed brick base with two concrete chambers acts like a woodburner, firing flames heated to 750 degrees up to the food and stones above. Cooking like this uses about 4kg of wood an hour, about quarter of that of the traditional umu - a big plus for islands running short of trees.

JOHN ETEUATI: We've got this combustion chamber here, and it's the primary combustion and the secondary combustion chamber. So the theory is you burn wood from the primary combustion, and any unburned smoke that comes up warm temperatures go through and go in as secondary air supply. So it just ignites the unburned smoke at a certain temperature. You burn the wood down there, the flames would reach up to this height.

Right. Almost like a metre up almost?

JOHN ETEUATI: Almost a metre up, yes.

So there's a lot of heat in there.

JOHN ETEUATI: A lot of heat, so it's clean-burning.

John Eteuati has handed his prototype oven over to this church who are now using it to cook for their big events. The minister, Reverend Posala Tioa,says he expects the invention to be a huge help to Samoa.

POSALA TIOA: Because we keep on cultivating the land, cutting the trees is the only way to generate the fires for us back home, because it's an open invention. A 75% in the use of firewood would be a huge help for our environment back home.

The oven was a final year project for Mr Eteuati's Bachelor of Engineering Technology course at Otago POlytechnic. His head of school, John Findlay, says it's an excellent piece of low-cost engineering.

JOHN FINDLAY: He's taken a complicated idea, but made it relatively simple. The materials that he's sourced to use, the shells in there as heat insulators, et cetera. He's used materials that are readily available in the islands so they can be relatively cheaply built.

Mr Eteuati has got the oven's cost down to about $170 and is patenting the design and thinking big. He say he plans to produce it in Samoa for his home country first, then find ways to spread it to every umu-loving country in the Pacific.