A physicist has teamed up with a bakery to create the first ever formula for making the ultimate sandwich – with no sogginess.

It just looks like a mathematics nightmare to us, but we are assured this set of squiggles is the holy grail to making the perfect sandwich.

Dr Mark Hadley, a researcher at the University of Warwick's Department of Physics, explained: “In principle, this formula will also describe the butter seeping into the bread, particularly as it warms up because D can depend upon temperature.

Scroll down for an equation key, a poll and a gallery of "sandwich personalities"

"At the interfaces we have a physical and chemical reaction of absorption. The reaction rates depends upon the concentration in the air and the activation energy, Ea, and the area exposed to the air.”

While this groundbreaking collaboration between bakeries and boffins is no doubt a ploy to sell more bread, it seems these tips could actually work.

Thankfully, for those of us left flummoxed by the formula, Hovis, the bakery in question, has simplified things:

  • Pressure: Don’t apply unnecessary pressure (the p(x,t) term) it squeezes out the water
  • Freshness: The equations describe the deterioration with time due to slow diffusion of the moisture, so eat your sandwich while it is fresh
  • Butter: Use a thick layer of butter, it is hydrophobic and keeps moisture away from the bread
  • Moisture: Control the loss, or uptake, of moisture from the air into the bread, butter protects the top, crusts are good; they stop the edges drying out (φair < φbread) or going soggy (φbread < φair), wrap the sandwich tightly to keep air away from the underneath – but don’t squeeze it of course
  • Temperature: Most equations are temperature dependent particularly viscosity and absorption rates, keep it cool to reduce the reaction rates.
  • Bread: Use the right bread, a thicker slice like in Hovis British Farmers Loaf (fancy that!), has a greater resistance to dampness and can’t dry out so quickly either

The formula comes in the back of a survey that revealed the average Briton wolfs up to 240 sandwiches a year, equating to a staggering 19,200 sandwiches in a lifetime.

It may be a full 250 years since the fourth Earl of Sandwich is said to have demanded cuts of beef be brought to him between slices of bread so he needn't take a break from gambling, yet the bread-based snack has since become one of Britain's most popular and enduring culinary creations.

The survey of 2,000 Brits was commissioned by Hovis to mark a search for the Ultimate British Sandwich, celebrating British Sandwich Week and the launch of the brand’s all new Hovis British Farmers loaf.

Sarnie, butty, bap, cob, whatever you call it, Brits are sandwich mad with over a third (33%) choosing to chow down on one at least four times a week, often forming the backbone of many a lunch break.

When it comes to the "perfect" sandwich the majority of Brits agree it’s got to be homemade (62%), cut in triangles for optimum taste (45%), with the crusts left on (78%) and butter, not margarine, is the spread of choice (41%).

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Traditional cheese and pickle (16%) topped the fillings poll, closely followed by the classic BLT (12%). The quintessentially British cucumber sandwich came in last place with just 1% naming it their favourite filling.

Almost three quarters (71%) cite soggy bread as the top sandwich bug-bear along with the bread falling apart (38%) or it being packed with too many fillings so it becomes messy to eat (22%).

These butty faux pas have lead to over a quarter of Brits (26%) developing precise rituals when preparing their perfect sandwich.

Taking care to avoid sogginess, a fifth (20%) ensure the entire surface of the bread, right to the corners, is covered evenly with spread and a further tenth (10%) dry ingredients, like tomatoes, on a slice kitchen roll (9%).

Other sandwich quirks and foibles include: always using butter and mayo together (12%), using different utensils for every condiment (11%) and uniformly cutting all the fillings to such certain thickness (10%).


Quick Poll

What's Your Favourite Sandwich Filling?


Click below to view a slideshow of “key sandwich personalities” as identified by bread-maker Warburtons last year.

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  • Tuna And Sweetcorn

    Individuals that pick tuna and sweetcorn on white bread love order, routine and targets. They can often find it hard to relax, work ahead of deadlines, can be high achievers and have a tendency to believe they are always right. They enjoy a range of hobbies and seek friends who share the same drive and beliefs as them.

  • BLT On Seeded Bread

    The BLT on seeded bread eater lives in the now, believing that experience speaks louder than words. Those that pick this sandwich are often self-indulgent and materialistic. They love eating out, films and live music. A good sense of humour in friends and partners is a must.

  • Cheese And Pickle

    Those who go for the classic cheese and pickle are logical planners who like to surround themselves with successful people. They tend to be good at tasks and will always tell the truth no matter how tactless it may seem. They love solving things and are a fan of games and puzzles.

  • Prawn On Brown Bread

    Those who pick a prawn sandwich on brown bread are friendly and tactful in any situation. They are sensitive and tend to be very unsettled by conflict. The need to agree with others can make them easily led. They love fashion and shopping and seek friends with a good sense of humour.

  • Beef Roll

    The beef roll lover acts first and then thinks later. They love to solve problems and are great at multi-tasking. They often have an unwillingness to commit to anything that will interfere with their freedom. In a partner they seek someone who is attractive and they enjoy the thrill of spectator sports.

  • Ham On White Bread

    The ham salad on white bread lover often spends time thinking about their future. They are inventive and original. A real love of physical activity and the outdoors, they gain inspiration from their surroundings at the expense of observing and experiencing them.

  • Chicken Wrap

    Those who pick a chicken salad wrap are sociable and talkative and thrive on interaction with the outside world. They do tend to act without thinking things through. They enjoy spending time watching sports and seek a partner with a strong career success.

  • Egg Mayonaise

    Those who prefer an egg mayo on wholemeal are reflective, quiet people, they like to spend time alone and are motivated by private, internal goals. They find social situations draining and instead prefer to spend time at home. In a partner they seek someone with similar interests and values to themselves.