What you always wanted to know...How to make the 'perfect' bacon butty!

Scientists in Britain have come up with a mathematical formula for making the perfect bacon sandwich.

This has been no easy task and has taken the team of experts at Leeds University more than a thousand hours of testing 700 variations on the traditional bacon sandwich to come up with the perfect format.

The four researchers at the Department of Food Science say the secret to the ideal sandwich is how crispy and crunchy the bacon rashers are.

Their advice to achieve the ideal result involves two or three back bacon rashers cooked under a preheated oven grill for seven minutes at about 240C (475F) then placed between two slices of farmhouse bread of 1cm to 2cm thickness.

The researchers tried different types and cuts of bacon, smoked, unsmoked, streaky and thick cut; different cooking techniques, frying, grilling, oven cooking or microwaving types; and different types of oil, sunflower, olive, vegetable..... along with a range of cooking times at different temperatures.

They devised a shortlist which was then tested with computers to measure the texture of each sandwich.

They recruited fifty volunteers to judge each sandwich according to taste, texture and flavour.

Lead researcher Dr. Graham Clayton says they found that it is not in fact the taste and smell of bacon that consumers find most attractive but the texture and the crunching sound of the bacon.

Brits spend more than £1bn on bacon every year and it is the UK's most frequently eaten meat.

The formula by the way is: N = C + {fb (cm) . fb (tc)} + fb (Ts) + fc . ta, where N=force in Newtons required to break the cooked bacon, fb=function of the bacon type, fc=function of the condiment/filling effect, Ts=serving temperature, tc=cooking time, ta=time or duration of application of condiment/filling, cm=cooking method, C=Newtons required to break uncooked bacon.