http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2006/07/31/negg31.xml The egg that will tell you when it's perfectly boiled By Brian McGinley (Filed: 31/07/2006) It could be an answer to the prayers of people who, quite literally, cannot boil an egg. Or at the very least, a godsend for a new generation of students struggling with the most basic of culinary tasks. Revolutionary "self-timing" eggs designed to overcome the perennial problem of how to avoid runny whites and overcooked yolks will appear on supermarket shelves in the coming months. Perfect every time: an egg cooked with the new label The eggs are marked with logos in "thermochromic" invisible ink, which turns dark when it reaches a certain temperature. Inks have been created to appear after three minutes to indicate a soft-boiled egg, after four minutes for medium and after seven minutes for a hard-boiled egg. Shoppers will be able to buy the eggs of their choice in cartons marked "soft", "medium" or "hard". The project was launched by the quality assurance scheme Lion Quality Eggs in response to thousands of people asking how to boil eggs properly. Gilly Beaumont, of B&H Colour Change, which developed the logos, said: "We are still perfecting the technology, but we are very excited at the prospect of sorting a problem that has wound people up at breakfast time for decades." The egg logos are the latest application of heat-sensitive technology, which is likely to transform future kitchen landscapes. Other inventions include oven gloves that not only have temperature sensors built in, but also "talk", with phrases such as "The food should be checked in 40 minutes". Scientists have also been exploring the use of thermochromic technology on fire doors that change colour when hot, football jerseys that can tell when a player is overheating and on road signs that change colour to indicate icy road conditions. NestlÃ© Rowntree has experimented with thermochromic logos on its chocolate wrappers in an attempt to cater for consumers who hate a soft KitKat bar. The label is printed directly on to the wrapper. Once placed in the fridge, the bar cools down while a note appears indicating that the chocolate is ready to be eaten. Such materials have already been used for some time on a range of products, such as for chill indicators on beer bottles and as safety features on baby spoons. Meanwhile, a student has come up with a device designed to solve the morning-time conundrum of how best to soft-boil an egg. The PerfEGG device keeps water temperature constant for 8.5 minutes without reaching boiling point, which aims to let the egg white coagulate but keep the yolk runny, regardless of egg size. The timing of the device can also be adjusted for hard-boiled eggs. Brunel University design student Ben Harris, 22, from Dublin, is in talks about launching his gadget. He said: "I love soft-boiled eggs with toasted soldiers but I get so frustrated if I get the timing wrong and the egg is too hard to dip my soldiers in."