We got a scoop from five fish 'n chip shops in Palmerston North and weighed them to find out what this means.

A classic Kiwiana culinary measurement is under scrutiny, with an industry educator calling for a scoop of chips to become standardised.

A Stuff survey of five fish 'n chip shops in Palmerston North found a scoop of chips, while costing $3 at each shop, could weigh as little as 363 grams and as much as 480g.

None of the stores displayed information saying how much a scoop would weigh.

MURRAY WILSON/STUFF Reporter Jono Galuszka investigates what customers can expect to get for a scoop of chips.

The Chip Group training and education manager Kate Underwood said variation in scoops was rife.

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The last survey the group did found a cooked scoop ranged from 280g to 800g, she said.

MURRAY WILSON/STUFF How big is a scoop of chips?

"It is the one thing in New Zealand you go to buy and have absolutely no idea how much you will get."

Having different sizes shop-to-shop made it tricky for customers to know how much to order, so they would either throw out food or think they had been short-changed, she said.

The group had spent years advocating for people to make a scoop 330g of uncooked chips, which would become slightly heavier as they absorbed oil while cooking.

Underwood said 330g was about what you got in a cup at a sports event, and was an appropriate serving for one person.

It was also a good size for cooking frozen chips. A scoop too big would see the oil cool too much, resulting in soggy chips, she said.

Shops with the best chips often used scales, which they would weigh chips on before they went to the fryer.

That also helped with consistency between different kinds of chips, like straight cut, French fry and curly, Underwood said.

"Maybe even weigh every one in 10 scoops, to get an idea of how many grams you are serving each time."

It could be hard for shop owners though, as customers may have become accustomed to larger sizes.

"A lot of owners get flack from customers saying 'that's not enough, give me more'," Underwood said.

"It is about the customers and the operators knowing [330g] is enough."

She said signage about scoop size could let customers know what they would get.

Fishtown Takeaway owner Gary Yeh said he aimed to serve at least 400g per scoop.

His staff were experienced enough to know how big 400g was in the scoop, and he would keep an eye on new staff.

"Sometimes new staff will give extra, but I don't mind that.

"We only give extra and don't give less."

Customers would sometimes say a scoop was too small, which could be down to them being used to takeaways from other places, Yeh said.

It was also tricky when customers asked for things like "$5 worth of chips", as it skewed the scoop system. Staff would have to try to figure out how much $5 worth was, then show that to customers, who might ask for another few dollars' worth, he said.

HOW MUCH IS TOO MUCH?

Statistics New Zealand includes fish 'n chips as part of the consumer price index, defining a meal as one fish and one scoop of chips.

The agency was unable to separate the fish prices from the scoop prices for Stuff, but its data shows the costs of the meal has gone from $4.38 in June 2006 to $6.47 in December 2017.

But tomato sauce has not been subject to inflation. In fact, a 560g can of the classic fish 'n chip accompaniment has gone from $3.03 in June 2011 to $2.84 in December 2017.

The index does not measure other condiments people may have with their fish 'n chips, such as mayonnaise, aioli or lemons.