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2EnginEEring CheMistry

hv t fa of molculagaonom, and an adm of McalFaada. h, alk o Amy Spulabou mod, and ppa apcal d ju fo E&T.

ow o

conuca mal

SCONES do not exist,announces Herv This

dramatically.

We are at the IETs Savoy

Place premises, where Dr Herv

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 3

ofE&T). He has so far lectured

at Imperial College and Le

Cordon Bleu culinary school inMarylebone Lane, London.

But back to scones. What Dr

This means is that tradition is a

differs from every other. It isthe 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 tobring some precision to the

kitchen that he and Nicolas

Kurti invented molecular

were exploration, testing thestatus 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 distinc-

tion 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 SCIENCEOF COOKINGI want to know why grilling a

steak is chemistry and making a

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 givingiDJ

ennings

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22 EnginEEring CheMistry

F 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 cuisinesgreatest hitsHere are some more famous

molecular cuisine moments you

may be familiar with:

sb mm q. This isbecause 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 sixyears old.

W-bk Dr Thishas baked an egg for

an hour or two, at 65C,

which preserves the

yolks 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.

e mkm How does onesmoke salmon with an

electronic field? Dr

This stresses that this wasnt

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.

gadgetsAs 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.

MoleculargastronoMy, or things

to do With an eggThe following are all things that

Dr This demonstrated in his

Imperial College lecture.

e Dr Thiscalls 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).

M e It is possibleto conjure up an

astonishing one cubic

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.

Fm e Can beachieved by putting

egg white in the

microwave. At 100C

the proteins coagulate,

presenting a foam that can be

flavoured.

ub e AddingSodium 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.

e JPut a mayon-naise-like emulsion ofwhipped 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.

traditional WisdoM?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. Hes

unperturbed when his theories

turn out wrong it meanstheres 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.

W w bvb?d b p f k vb qk?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

d p p b fmp kp fzz?This notes that the tradition

specifies a silver spoon, but

actually it doesnt matter what

sort of spoon you use it still

wont 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 PhysiologySensorial 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 worlds

top 20 bartenders. Herv invited

the bartenders to taste a strongred wine, a light dry white and

water with 10 per cent ethanol.

They couldnt 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 Thiss, Gil Morrot,

has carried out more work on

this. He has coloured white wine

slightly green and discovered

that this gives people the impres-sion that it tastes acidic. Diners

were also found to be uncomfort-

able 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

Molcula gaonom no abou nvnon,bu abou dcov lfng a con of ga vl, a Alb

enn onc adHev Ths

am w bw k, v fv

1

2

3

1

2

4

5

3

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22

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) tostimulate 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.L

In front of the IET London officesstands a statute of Michael Faraday one the great physical chemists.But what would a dish calledFaraday look and taste like?

My field is moleculargastronomy the science of foodand physical chemistry, in partic-ular. It is nothing to do with thefashionable molecular cooking:cooking means preparing dishes,whereas gastronomy is reasonedknowledge concerning mansnourishment. Yes, indeed,gastronomy is nothaute cuisineand, just as molecular biology is amodern version of biology, molec-ular gastronomy studies mecha-nisms and chemical reactions ofcooking. Why do green beans turnbrown when overcooked? Whydoes souffl rise? Why does steak

turn brown upon grilling? This ismolecular gastronomy!

Molecular gastronomy is notabout inventions, but about discov-eries: lifting a corner of the great veil,as Albert Einstein once said. Howdoes it relate to technology then?Directly! For what is technology butapplication of new knowledge?

Let us now return to the Faradaydish. In 2002, I proposed at theEuropean Congress of InterfaceScience a new way of definingcolloids. The idea was to denotegases, liquids and solids by letters:respectively G, L (oil O, or water W),S and to link these symbols bysigns such as / (dispersed into), +(mixed with), @ (included in). Amayonnaise sauce could then bedescribed as O/W, for it is preparedby the dispersion of oil droplets in

an aqueous solution made fromegg yolk and vinegar.

Faraday dish would thencorrespond to the formula((G+O+S1)/W)/S2. It can beeasily cooked, using the followingrecipe:

First, make an emulsion (O/W),for example, using tea (for W) andan oil that was heated with shrimpshells; then add a solid, such asmeat of scallops (S) and whip themixture until it gets foamy (+G);Dissolve some gelatine in theaqueous solution used. A gel willthen form, to supply the final /S.This is a Faraday of scallops and tea!

Why Faraday? Thats hard toexplain. I simply wanted to honourthe great engineer and physicalchemist the true father ofmolecular gastronomy.

A Dish CAlleD FArADAyby herv ThisexClusively For e&T

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