Mutu's menu this year has featured beef Wellington, lasagne, scotch fillet, glazed ham, roast pork, lamb racks and, of course, hangi.
He said it was a whānau decision to take on the catering contract 12 years ago, and there was never any intention of making money out of it.
"If we wanted to make money we'd be having mince and whatever else every night ... but we choose not to go down that path and instead to give them the best quality that we possibly could."
Mutu's crew feed more than 70 people each morning and evening during the week.
But his whānau are used to catering for crowds.
"I was brought up on the marae with my parents and grandparents like everybody else, but Mum and Dad basically ran the kitchen and so that's where we got it from, it's about manaaki te tangata."
Karmen Wallace, volunteer coordinator at the waka loading bay at Lake Karāpiro, has been volunteering at the national champs for more than 20 years and said Mutu's kai was "tino reka".
"It is one of the drawcards for coming back each year and I don't say that lightly, it really is," she said.
Mutu's menu for the Friday night hākari (feast) alone would make the event worth volunteering for.
"Friday is basically surf and turf because one year we did all seafood and someone said 'I don't eat seafood', 'really?' So we'll have scotch fillet and then paua, scallops, oysters, kina, prawns and raw fish and sashimi."
Mutu said generally the core volunteers come back every year and have been for the past 20-odd years.
"The great thing is you see the kids grow up, they come in when they're five or six as a mokopuna of one of the others, next minute they're shooting right up, that's awesome."
Along with those core volunteers, Mutu and his crew will be back at Lake Karāpiro in 2022.
"It's a kaupapa you're either in 100 per cent or you're not. The great thing about this kaupapa is it goes basically from five-year-olds to 80-year-olds, it's a whānau kaupapa and definitely no other sport where they have all of them together."