A scientist in Nottingham has revealed the formula for the ultimate chip butty.
Dr James Hind, a statistician from Nottingham Trent University, has claimed to refine the perfect chip butty recipe based on preferences of 2,000 Brits surveyed by supermarket chain Iceland.
Scientists claim a faultless butty has 12 thick cut chips, two 40g slices of medium sliced white bread, ketchup and butter – not mayo or margarine.
Dr Hind calculated a scientific formula – C ≥ 3b/4 + k + 3m, where C is the weight of chips(g), b is the weight of the bread(g), k is the amount of ketchup (ml) and m is the mass of butter (g).
He said the optimum ratio of chips to bread by weight is three quarters, adding the weight of any ketchup to that of the bread.
So how do you make the perfect chip butty?
The step-by-step guide to creating the ultimate butty, according to the scientist is:
Cook thick cut oven chips at 200C for 22 minutes
Thinly butter two slices of medium sliced white bread
While the chips are freshly cooked, place at least 12 on one slice of buttered bread so that their weight is three quarters that of the bread plus ketchup
Squeeze as much ketchup as you like but add more chips to compensate so it doesn't get too cold
Place the second slice of bread on top of the still steaming hot chips
Allow to cool for at least 30 seconds before enjoying. If it is too hot to hold, it is too hot to eat!
Dr Hind said: "What makes white bread preferable is that it is usually the softest.
"This makes it a perfect contrast to the crunchy chips. And sliced bread has a constant thickness, giving a more consistent chip butty.
"The most important thing is to have the weight of chips at least three quarters of the weight of the bread plus ketchup.
"But every type of bread and style of chip varies subtly, so I'd encourage people to experiment at home and devise their own perfect formula.
"Personally, I much prefer brown sauce and you can substitute it for ketchup in the equation as you like.
"One thing my formula ignores is salt. That's a matter of personal taste – and personal health – and so that's a great place for people to start their own experiments!"