Today, millions of people will be assembling their favourite fillings between two slices of bread today in celebration of National Sandwich Day.
Surely there’s are few snacks that capture the world’s heart like the sandwich, which was allegedly devised by John Montagu, the 4th Earl of Sandwich, in 1762.
Famously, he was playing cards and did not want to leave the gaming table to eat, so he asked for a serving of beef placed between two slices of bread that he could eat with his hands.
More than 250 years later, fierce debate still rages about the best fillings, the art of construction, and even how to eat it.
Now, to settle the debate once and for all, food scientists have revealed the formula for the perfect sandwich.
According to the academics, the perfect sandwich has a symmetrical arrangement with the wetter elements placed in the centre.
These wetter elements tend to be the salad ingredients that give an essential crunch – so tomato, lettuce, or perhaps some gherkin or pickled onion.
‘Wet fillings, like slices of tomato, need to be sandwiched in middle and insulated from making the bread soggy,’ said Charles Spence, professor of experimental psychology at the University of Oxford.
According to scientists, the perfect sandwich has a symmetrical arrangement of fillings and between a robust bread spread with room temperature butter
During construction, rather than building your sandwich from the bottom up, you should place both pieces of bread side by side and add each filling sequentially.
‘The trick is to place both pieces of bread side by side, then spread, place primary fillers on each slice, and finally add salad in the middle and place them together,’ said Alan Mackie, professor of food and nutrition at the University of Leeds.
When choosing your bread, you need to opt for a loaf that won’t get squashed or soggy easily, such as sourdough, wholegrain or brown.
Professor Spence says: ‘The fundamental purpose of the Earl of Sandwich’s invention is to keep one’s hands clean, so that might rule out greasy breads such as focaccia.’
The two slices need to be not so thin that they risk falling apart, but not too thick that they’re too difficult to eat – about 0.7-inch (2cm) is the sweet spot.
Next, some kind of fatty emulsion essential element should be spread right to the edges of the bread.
This not only adds an unctuous fatty flavour but creates a seal that repels any moisture – another trick to help prevent the bread from getting soggy.
Professor Spence says butter should be the spread of choice over margarine which is an ultra-processed food, while another alternative, mayo, is ‘simply disgusting’.
You need to choose a robust bread that won’t get squashed or soggy easily. While the choice of fillings is a personal one, scientists think it’s important to consider how exactly they are arranged
The butter should be at room temperature (20°C/68°F) so that it’s soft enough for spreading, otherwise it could tear holes in your bread.
Your chosen meat and cheese, which also contain a good deal of fat, further prevent any unwelcome moisture from getting anywhere the loaf.
Professor Mackie thinks it’s worth folding your meat if you can rather than lying it flat, which creates more of a barrier.
But an additional precaution to ‘prevent the sog’ is to ensure you pat dry your lettuce, gherkin or onion with kitchen towel or use a salad spinner.
Meanwhile, tomato is a risky addition because it has so much water in it, which can also dilute the overall flavour of the sandwich – so you might want to heat it in an oven or a food dehydrator.
If this sounds like too much hassle, Professor Spence stresses that the salad is an essential element to deliver the ‘sonic crunch’ when bitten into, with greater noise linked to enhanced satisfaction.
‘Given that we all love crunchy, crispy, crackly foods, you should ensure some of the fillings appeal to the ear and help signal freshness,’ he said.
‘That is where gherkins come in, or a slice of fresh onion, although others cheat and add in some crisps in the middle of sandwich just before they eat it.’
Surely there’s are few snacks that capture the nation’s heart like the sandwich, which was allegedly devised by John Montagu, the 4th Earl of Sandwich, in 1762
Also, getting as wide a range of colours into a burger can ‘make what we eat look more attractive’, from the green of the lettuce to the red of the tomato.
‘The more vibrant the colours the better,’ Professor Spence told MailOnline.
‘Just think how dull a tuna mayo filling looks inside a white sliced bread sandwich.’
Eaters must also ensure that their fillings are always visible sticking out of sandwich to make it more eye-catching.
Finally, Professor Spence, who has written extensively about how people perceive food, warns that ‘adding more layers isn’t always better’.
‘Never forget the narrow size of the aperture in which the sandwich should go the mouth,’ he told MailOnline.
‘Make sure the whole hangs together so that the filling doesn’t fall out of your sandwich from plate to mouth.’
