STANDING between the bubbling heat baths and nitrogen canister, temperature probes and distillation equipment, you’d be forgiven for thinking that Heston Blumenthal’s workplace was a chemistry lab or the set for the latest remake of Frankenstein. Except for the sign over the door. Precious few scientists would call their lab The Fat Duck.
This is in fact Blumenthal’s kitchen at his Michelin-starred restaurant in Bray, Buckinghamshire. Blumenthal is a master chef with a passion for physics and experimentation – and a taste for the unusual.
“Madam, your meal is served.”
It doesn’t take long to forget the scary-looking kitchen as I tuck into a full English breakfast on posh white porcelain. First the bacon, which literally melts in the mouth. Then scrambled eggs, eggy bread and mushrooms on the side, and a mouthful of tea to wash it down. But there’s something funny. The tea is made of jelly. The bread is sweet, and the bacon and eggs are stone cold. Frozen, in fact. My breakfast is made of ice cream.
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Blumenthal loves confusing people’s expectations of a food’s temperature, texture and taste. He is a culinary postmodernist, mixing form and content, appearance and flavour. “I enjoy seeing how people react when they realise what they are eating is not what they thought. I want diners to be pulled out of their food comfort zone,” he says.
Blumenthal is also fascinated by how food works, how flavours are produced at a molecular level. He’s being helped in his quest, not only by his laboratory-style kitchen equipment, but also by Peter Barham, a polymer physicist at Bristol University. These “molecular gastronomers” say that flavour is a complex mix of senses – taste is just one. Smell, touch and temperature affect your experience, as do context, expectation and all the meals you’ve ever eaten. Blumenthal’s ice cream plays on all of these factors.
A flavour is also strongly affected by all the other flavours around it. This is where Blumenthal particularly enjoys bending the rules. The next course is a perfect example. Green mustard ice cream with gazpacho sauce made from red cabbage, and a crab ice cream with passion fruit jelly. Chocolate and thyme ice cream is waiting for dessert.
But Barham insists these flavour combinations are not as unusual as they might sound. Flavour preferences are often cultural rather than innate. For example, he says Japanese people may think sweet rice pudding tastes unpleasant because it’s an unusual experience for them. But you can acquire a taste for any new food. Tony Blake, vice-president for Food and Science and Technology for fragrance manufacturer Firmenich, in Geneva, says that given time, “your taste buds can get used to anything which has nutritional value”. He gives the example of orange juice and cod liver oil that British schoolchildren were forced to swallow after the Second World War. “This combination actually started to taste OK,” he claims.
Culinary history is riddled with opposing tastes grouped together: sweet with sour or sour with bitter, for instance. This “dynamic contrast” is what makes food interesting. Some chemical interactions between different flavour types change the taste of food as well. Salt actually suppresses some bitter flavours and enhances sweetness, which makes food more palatable.
Molecular gastronomers believe foods will seem right together, not only when flavours work in harmonious opposition, but when foods share more than one-quarter of the same flavour molecules. Blumenthal sees caviar and white chocolate as a happy union. “There are about 560 compounds in cocoa and 60 in caviar. But over a quarter of the flavour molecules in cocoa and a quarter of those in caviar are similar in structure.” Blake isn’t so sure that’s the reason these wacky combinations taste good. “Blumenthal’s recipes are more art than science,” he says.
There’s one last element of flavour that Blumenthal enjoys experimenting with – the timing. The bacon and egg comes in a single ice cream. But when I bite it, it’s the bacon flavour that hits my taste buds first, then thirty seconds later, the egg. He explains that it’s the size of molecules in an emulsion like ice cream that determine how long it takes for the brain to register taste. Bacon comes first because the flavour molecules are smaller.
There are no pieces of bacon – Blumenthal makes the ice cream by boiling milk with fried bacon so it takes up the flavour. He adds egg yolks to the mixture and cooks it until the eggs almost scramble. Then he purees, sieves and freezes the mixture.
In physical terms, ice cream has four phases, ice crystals, crystalline fat particles, air bubbles and sugar dissolved in water to keep it liquid. The flavour molecules are divided between the sugar solution and the fat. Chris Clarke, a polymer physicist at Unilever says, “with ice cream, it’s all about making and breaking stability. Ice cream must be stable enough to be stored and maintain its structure, but unstable enough to release flavours.”
Clarke says that this delicate balance is incredibly hard to produce. “Ice cream is not thermodynamically stable. Its ‘crazy paving’ of ice crystals and air bubbles are kinetically trapped,” he says. The temperature of the ice cream has to be about -10 °C to keep its crystal structure.
According to Barham, the crystals in polymers like ice cream grow extremely rapidly, which makes creating a smooth ice cream a real art. You need ice crystals at most 0.1 millimetres in diameter, so that there’s no crunching sensation when you take a bite. “This is very difficult,” says Barham, “as ice crystals do not like being small.” You either have to churn the ice cream as it freezes, or add impurities, such as milk powder, to stop the crystals from growing. Alternatively, you can lower the temperature very quickly, so that lots of crystals begin forming at the same time, limiting each other’s size. Blumenthal’s novel solution is to freeze the mixture with liquid nitrogen in a canister that once belonged to a doctor who used its contents to remove warts.
Keeping these ice creams in perfect condition for any length of time is even more tricky, according to Clarke. So you’re unlikely to see Blumenthal’s novel ices on the supermarket shelves anytime soon. Clarke used to work in the aerospace industry as a plastics expert. But making ice cream that will survive life in such varied temperature conditions as the factory, delivery van, supermarket freezer cabinet, and your shopping bag is so very much harder, he says. “At -10 °C, you try maintaining structure of one of the most delicate crystal structures on Earth.”
