Science in the kitchen

Laboratory News investigates an emerging scientific discipline which focuses the science of cooking and why certain foods taste good and others bad

They say the way to a man’s heart – and perhaps even a woman’s – is through their stomach, and in a world where the waistline is ever increasing this seems to ring true today, but its only relatively recently that people have begun to show an interest in how food is prepared and why certain foods taste so good.

The science of molecular gastronomy focuses on the ‘mechanisms of phenomena occurring during culinary transformations’ – in other words, how and why cooking affects our enjoyment of food. The term was coined in 1988 by Hungarian physicist Nicholas Kurti and French physical chemist Hervé This. It became the title for a series of workshops held in Italy that bought together scientists and professional cooks to discuss the science behind traditional cooking preparations.

Molecular gastronomy investigates issues like how different cooking temperatures change the ingredients, how our senses affect our appreciation of different foods and how aroma release affects our perception of taste and flavour.  Hervé This discovered that the optimum temperature for cooking an egg is 65°C – the white coagulates but the yolk remains runny – and an electric field improves the smoking of salmon.

Combining science and cooking is not something new but the emergence of this new area of science is. Many may think molecular gastronomy is just a convoluted term for food science but the two are about as similar as chalk and cheese:

“Food science is generally (but not exclusively) concerned with large scale food production; molecular gastronomy is concerned specifically with food of gastronomic quality,” said Professor Peter Barham, senior tutor of physics at the University of Bristol.

So while food science concentrates on nutrition, food safety and the production of food on an industrial scale, molecular gastronomy is more about why some food tastes good, why some tastes bad and why we enjoy food.

“I prefer to think of molecular gastronomy as an emerging scientific discipline where people from a wide range of areas collaborate with chefs and other cooks to try to understand the process that makes food of gastronomic quality – at home and in a restaurant – and try to answer the fundamental question as to why some foods taste delicious while others do not,” Barham said.

In an article on the Discovery channel website Barham said: “To me a kitchen is just like a science laboratory and cooking is just another experimental science.”¹ He goes on to say it’s a bit like a chemistry lab, full of chemicals, containers, devices to control measurements and reactions and those to decipher your results. “Every time you follow a recipe you are conducting an experiment,” he said, “You measure out the ingredients, mix (or react) them together following the instructions and then test the result – by eating the resulting dish.”

Barham is also a visiting professor of molecular gastronomy in the food science department at the University of Copenhagen, and has recently published a study in Chemical Reviews titled Molecular Gastronomy: An Emerging Scientific Discipline.
“ It is the first major output of the collaborations between myself and people working in the department,” he said, “It is intended both to review the current state of research relevant to molecular gastronomy across the world and to set out a ‘manifesto’ for future work in the area.”

The study looked at how chemistry and other sciences involved in cooking are making an impact in the public arena. It also looked at how novel applications of existing science can help chefs create new dishes and extend the range of cooking techniques available to them.

Tried and tested methods have been handed down from generation to generation – nothing rivals one of your mum’s home cooked meals. But perhaps mum’s cooking isn’t always correct – molecular gastronomy has debunked some of the myths you’ve probably heard of or had handed down, like adding salt to water before cooking green vegetables, and searing meat to seal in the juices.

It was this last point that prompted TV chef Heston Blumenthal to take a scientific approach to cooking².  While reading On Food and Cooking by Harold McGee, Blumenthal read: “We know for a fact that searing does not seal,” and this encouraged him to ignore, bend and most certainly break many of the ‘rules’ of the kitchen. It was a move that worked as Blumenthal is owner and chef of world-renowned restaurant The Fat Duck and has his own TV show where he gets to play scientist and chef in an attempt to create weird and wonderful dishes for celebrities.

Barham has worked with Blumenthal for many years and introduced him to many scientists who helped the self-taught chef understand the science behind cooking.
“Years ago Heston was looking for a scientist who could help him understand what was happening in his kitchen – his initial question was in fact about the cooking of green beans,” said Barham, “He realised for himself there was no good reason to add salt to the water, but wanted to understand why everyone in the profession said it was essential.”

Textbooks advised chefs to bring a pan of water to the boil before adding a handful of salt to stop the water coming off the boil when the beans are added, explained Barham. Once the beans were cooked chefs would plunge them into iced water and store until needed during service, when they were plunged back into boiling water. The salt does nothing for the flavour, and the cold water removes traces of the salt – in blind taste tests no-one can tell the difference between beans cooked with salt and those without.

The textbooks say the salt helps to fix the colour of the beans, and Barham says this is where the real clue lies –salt was used to remove impurities, including soluble salts of magnesium and calcium. “These divalent ions can interact with the chlorophyll in green vegetables and change its shape so it actually appears greener,” Barham said, “You can take old brown coloured vegetables and by cooking them in dilute solutions of calcium citrate make them go green again. They may taste bad, but they look good!”

Barham still works with Blumenthal from time to time: “When he has a question he needs to know the answer to he will turn to me,” said Barham, “But these days he has a really large network of scientists all anxious to work with him!”

So some of these tried and tested methods might have worked once, but as times have changed they are beginning to be ignored. Cooking has also changed dramatically since the emergence of new food preparation and storage methods such as microwaves, vacuum packing machines and induction heating. As Barham points out, if we always relied on these supposedly perfected methods, we’d still be cooking over open fires holding our food on long wooden sticks!

Ferran Adriá is owner of El Bulli – the Spanish equivalent of Blumenthal’s Fat Duck. With a restaurant in Roses, Girona and another in Barcelona, Adriá is well known for creating culinary foams and unusual concoctions. Adriá is keen to share his knowledge and El Bulli’s website defines some of the important points to remember while creating a culinary masterpiece of gastronomic quality:

• All products have the same gastronomic value, regardless of their price.

• Although the characteristics of the products may be modified (temperature, texture, shape), the aim is always to preserve the flavour
• The information given off by a dish is enjoyed through the senses; it is also enjoyed and interpreted by reflection³.

And it’s this last point which is most notably practiced by Blumenthal. In his TV show – Heston’s Feasts – Blumenthal not only creates unusual dishes by unusual means, but creates an overall feast for the senses. Take for example Heston’s Chocolate Factory Feast. Not only did he create lickable wallpaper – flavoured with prawn cocktail, lemon and sausage – he served a magic mushroom garden-inspired soup starter and a duck filled orange capsules wrapped up like a chocolate orange, a nod towards the popular dish of the time – duck a l’orange. And to top it all off there was boozy chocolate waterfall that unmixes, leaving dry alcohol-laden chocolate powder and a clear chocolate water.

From watching the program, it was clear that the celebrities didn’t know what to do with themselves – they were completely overwhelmed by not only the food, but the presentation and overall spectacle of the evening. And sure, there was a certain amount of creative flair that went into the packaging and presentation of Blumenthal’s meal, but the science behind the creation is potentially achievable on a less grandeur scale.

Whilst their menus are incredibly impressive – and undoubtedly extravagant – neither Adriá nor Blumenthal likes to be associated with the term ‘molecular gastronomy’. They both take a scientific approach to their cooking, but believe the term is elitist and pretentious and makes the technique sound more complicated than it is.

Whether they like it or not, Blumenthal and Adriá continue to be linked to molecular gastronomy and are perhaps in some small way responsible for bringing scientific know-how back into the kitchen – both in restaurants and at home.  While we know we can’t recreate dishes on the same scale that they do, there’s no reason why we can’t learn to appreciate some of the basic elements of this emerging science and adapt it to our everyday cooking – after all, who doesn’t want a chocolate waterfall at their dinner table?