There are no Oompa-Loompas in evidence on this Reading University campus, but one laboratory tucked away on the site is doing work that would be sure to set Willy Wonka's pulse racing.

Inside, researchers working for the owner of Cadbury are testing the crispiness of biscuits, analysing the molecular structure of chocolatey aromas and calibrating the crackability of Easter eggs.

Chocolate eggs are being peered into through electron microscopes that, through a haze of liquid nitrogen, reveal the precise distribution of air bubbles and sugar crystals inside, while other eggs are assessed by probes that gauge exactly the force that will be required to bite through them on Sunday morning.

It is all vital information for the manufacturer which turns out nearly 50 million chocolate egg shells a year at its Bournville factory, Cadbury's historical home.

The Bournville site, where 350 million Creme Eggs also roll off the production lines, does the bulk of chocolate R&D, but the products come to Reading for analytical testing and work on sensory perception.

One senior scientist presides over a gas chromatography and olfactory machine. A graph on a screen shows the individual flavour components that are being pumped into a nozzle to be assessed by the sensitive noses of trained testers in white coats and goggles.

"Our machines allow us to gain understanding on a molecular level and then tweak recipes. It's very important to deliver the signature flavour profile," flavour chemist Andreas Czepa says.

“You can compare it to an orchestra. The flavour components are the instruments, the flavour profile is the melody. Just one instrument by itself is not exciting but together the different instruments can create flavour profiles. If you took one out the flavour profile would lack depth.”

Here, the human role – smelling the components – is obvious, but all the site's scientists say co-operation with panels of tasters is a vital part of the research. The technology recently helped with the launch of Oreos in China.

Mondelez – the sweets and snacks part of America's Kraft, which controversially bought Cadbury in 2010 – spent $471 million last year studying its huge range, from Ritz crackers and Philadelphia cheese to Kenco coffee and Cadbury chocolate. The Reading labs have created about 100 jobs since 2011, said managing director Alan Gundle.

One of his team’s recent assignments has been to scrutinise the Egg ‘n’ Spoon, a purple cardboard egg box containing four Creme Egg-sized chocolate eggs filled with mousse and sold with miniature spoons.

When the Egg ‘n’ Spoon hit the shelves last year it was the culmination of one strand in a multi-million pound research programme. Mondelez says the little box of eggs is “shaping up to be a £5m brand in the UK.

If current trends continue, the results after Easter are likely to show it has tripled sales in one year.” Gundle adds: “In 2012, sales of products developed in the previous three years accounted for 12 per cent of Mondele-z Europe’s revenue and 13 per cent for the company worldwide.”

Part of the work on the Egg ‘n’ Spoons used techniques borrowed from 3D medical imaging used to look for tumours and assess bone damage. The centre’s tomography machine, like a smaller and more powerful CT scanner, takes pictures that can show details as small as 1,000th of a millimetre.

Sarennah Longworth-Cook, a senior scientist, explained how a tomography machine – like a smaller and more powerful medical CT scanner – took images of a product such as the Egg ‘n’ Spoon egg to a resolution of 10 microns.

“It shows structural information of what is going on visually, and quantitative numbers that show the distribution of bubbles and the pore volume,” she said. “We then feed back information to the product developers of the texture that gives the consumer experience we’re looking for. We can do shelf-life studies to see what happens to the product over time and we can see how the chocolate behaves in hot climates.”

Cadbury has been making Easter eggs since 1875 – an expensive process at the timemaking fragile dark chocolate shells – but has to maintain its share of “Easter innovation”.

In the lab eggs are subjected to a machine that pushes a vertical probe down into the outer shell, measuring how much force is needed to crack through it.

Bogdan Dobraszczyk, another senior scientist, explains they use the machine, a "stable microsystems texture analyser", to assess not just hardness and softness, but the vital crispiness of biscuits: "It measures texture, hardness, crispness, key attributes especially for snack products like biscuits. It's about trying to put some numbers on it – measuring the force."

The expertise here is not easy to come by. Miles Eddowes, associate director of R&D and quality at Mondelez, said: “We need top-class scientists to continue doing this. The problem is top talent doing science degrees at university going to do other things.”

Jacinta George, head of ingredient research at Mondelez International, added: "The quality and depth of science in the UK is world class, but we can see gaps in areas of food science. We are working with universities on making sure their programmes are tailored to generate new graduates in these fields."

Tax credits for research are helping, said Gundle. “[THEY] enable you to get some scale,” he said. “We are competitive with our peers on R&D as a percentage of turnover, at about 1%. But there’s only so much you can afford. If R&D tax credits help you get a few more projects and a few more people that helps.”

Lee Hopley, chief economist at the manufacturers' association EEF, said last April's move to raise the R&D tax relief to 10% was a "fairly significant change. Tax credits do help with cash flow. Manufacturing invests proportionally more in R&D than other sectors so you would expect a proportionally greater benefit."

Beyond Easter, chewing gum that keeps its freshness for 40 minutes has been a big success in Europe, Gundle said, while heat-resistant chocolate for hot countries was set to be a "breakthrough product". But some products would never change: "Dairy Milk is perfect as it is. Some products are ring-fenced for historic perfection."

Guardian