Herve This on the physical chemistry of food.
'Scones do not exist,' announces Herve This dramatically
We are at the IET's Savoy Place premises, where Dr Herve This is very pleased to discover a statue of Michael Faraday outside the building. This physical chemist calls natural philosopher Faraday 'the most important physical chemist'. Dr This is on a mini-tour to promote his new book, 'Science of the Oven' (reviewed in issue three of E&T). He has so far lectured at Imperial College and Le Cordon Bleu culinary school in Marylebone Lane, London.
But back to scones. What Dr This means is that tradition is a fallacy; each batch of scones differs from every other. 'It is the old debate between Plato and Aristotle - what is the taste of a cherry? All cherries are different, so there is no taste of the cherry.' Tradition is one of the things This is trying to update. Especially since certain things in our kitchens have been around since Medieval times. 'Down with the Middle Ages!' he said in his London University lecture. This has collected over 25,000 old French cooking customs, which he calls 'culinary precisions', and which he is testing out. It was to bring some precision to the kitchen that he and Nicolas Kurti invented 'molecular gastronomy' in 1988. Their aims were exploration, testing the status quo, introducing new tools and ingredients and spreading science through food.
Out of this came 'molecular cuisine', practised by high-profile chefs worldwide, but This is keen to assert the distinction that molecular cooking is cooking and molecular gastronomy is scientific activity. 'Molecular gastronomy is not cooking for rich people,' he said in his Imperial College lecture.
The science of cooking
I want to know why grilling a steak is chemistry and making a mayonnaise is physics. 'Grilling a steak is cooking,' This laughs. I have asked what he calls a 'Strawberry and Blackcurrant' question. His son once asked him if he preferred raspberries or blackcurrants and he chose strawberries. Dr This explains the significance: 'Escape the box! Or there is no invention.'
However, he does concede that when a mayonnaise fails, it is physics, since there has been no molecular transformation or new compounds. Whereas when a steak browns, there is atomic rearrangement - more precisely the famous Maillard reactions, discovered by Louis Maillard, where amino acids react with sugar when heated, giving flavour. For the physicist, there are universal rules that apply, This continues, and for the chemist 'the devil is in the detail, rules are always wrong, he is trying to focus on the exceptions'.
Molecular cuisine's greatest hits
Here are some more famous molecular cuisine moments you may be familiar with:
Sorbet and ice cream made using liquid nitrogen
This is because liquid nitrogen, at -196C, produces tiny crystals, which Dr This describes as 'like velvet in the mouth', whereas your average barely-below-zero freezer produces large ice crystals, which are not so pleasant to eat. Dr This performed an experiment with a salt crystal in a saturated solution of salt and watched it turn into a mono-crystal when he was only six years old.
Dr This has baked an egg for an hour or two, at 65C, which preserves the yolk's liquid yolkiness and keeps the white milky and delicate. He regularly cooks joints of meat for a whole day. He recommends this method to preserve both taste and money, explaining that proteins are hydrolised during long cooking, creating amino acids, which add taste. Also, when one boils a 1kg piece of meat, its mass is reduced by 30 per cent, whereas if you cook it slowly at 60C or 70C then only 5 per cent is lost. 'This is what I do at home,' he says.
Electronically smoked salmon
How does one smoke salmon with an electronic field? Dr This stresses that this wasn't his invention, but it is a shortcut to smoking an already-dried fish. It is done by directing smoke through an iron grid to a battery, positioned on an iron belt. The charged smoke particles then become drawn through the fish.
As we have already discovered, Dr This has been in the lab since the age of six. When did he realise that equipment from the lab could also be used in the kitchen? He says that, as a student, he had only one room. More precisely: 'All my lab was in the room but it was the room where I cook.' Not only did he not have to acquire kitchen utensils, but laboratory instruments such as thermometers, beakers and water baths have the advantage of offering much greater precision than your average oven or pair of mechanical scales.
Molecular gastronomy, or things to do with an egg
The following are all things that Dr This demonstrated in his Imperial College lecture:
Dr This calls this 'Thenard', in honour of famous chemist Louis Jacques Thenard. Poach an egg by pouring ethanol onto a raw egg in a beaker. The proteins then coagulate with the ethanol (though if you want a better flavour, This advocates using a strong whiskey).
It is possible to conjure up an astonishing one cubic metre of egg white from just one egg: Whisk a 30g mass of egg white with water and sugar. Dr This has been known to keep going until he has added 27l of water, although at the Imperial College lecture he was more restrained.
Can be achieved by putting egg white in the microwave. At 100C the proteins coagulate, presenting a foam that can be flavoured.
Adding Sodium Chloride (or Vitamin C) to an egg unlinks the protein molecules, which have linked up and enclosed water during boiling. It takes about three hours for the protein molecules to detach.
Put a mayonnaise-like emulsion of whipped egg white and oil in the microwave until it swells, showing that it had reached boiling point (after a minute or so). When he took it out, it was like jelly.
'I hate tradition that is not filtered by judgment,' says This. To this end, he is applying science to his collected 'culinary precisions' from 100-300-year-old French cookery books. He's unperturbed when his theories turn out wrong - it means there's room for more experimentation. And 'when I have no idea - I love that also!' he laughs. I decide to try out a couple of received kitchen 'wisdoms' on him.
Why do we add salt to boiling vegetables?
Does it raise the boiling point and therefore cook our vegetables quicker?
Dr This replies that you would need an awful lot of salt - he thinks about 250g to 200g water - and the boiling point would still only be raised by about 3C. Otherwise, adding salt actually lowers the water temperature by 1-2C because the salt takes energy to dissolve.
Does putting a spoon in a bottle of champagne keep the fizz?
This notes that the tradition specifies a silver spoon, but actually it doesn't matter what sort of spoon you use - it still won't help. He explains it is best to just reclose the bottle and keep it cold, like everybody else.
This has been shown to be the most effective by measuring the pressure of the gas in the champagne.
Sensorial physiology is the perception of taste. Taste, sound and sight are all in the same part of the brain. So your vision and your ear also affect your perceptions of taste. Dr This gives an example of the importance of sight. He tells the story of when he was invited by the Bols Corporation to give a lecture at the Ritz Hotel, Paris. The audience was the world's top 20 bartenders. Herve invited the bartenders to taste a strong red wine, a light dry white and water with 10 per cent ethanol. They couldn't tell the difference. They smelt them - 'nobody could tell', says This. They tasted them - 'nobody could tell'. The reason was because they were tasting in the dark. Without the strong visual pointer, their taste buds were apparently also in the dark.
A friend of This's, Gil Morrot, has carried out more work on this. He has coloured white wine slightly green and discovered that this gives people the impression that it tastes acidic. Diners were also found to be uncomfortable in a room where everything was green. It coloured their perception of the food too, says This. And not in a good way.
So sight does affect your taste perception. But what about sound? Can it also heighten or dull the eating experience? Heston Blumenthal has played with the relationship between taste and sound in his Berkshire restaurant, often giving diners headphones with their meals to heighten the eating experience. Dr This says you can try this at home with a laptop, earphones and some crackers. If you 'eat crackers with a soft noise - you have the feeling that they are not very fresh.' Touch can have a similar sensory effect - stroking velvet while eating ice cream, for example, can make the food seem silkier.
The future of food?
Culinary Construction or 'culinary building', as This calls it, is all about the sensory effect. Food is built (or constructed) to stimulate - so the taste of an ingredient on top may actually be perceived after something else, flavours will be longer and mouth and eye will work together - the dish will be constructed to visually wow, as well as orally. This, according to Dr This, will be the next food revolution. Food as art. Food for thought.
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