Hollow Inside: Starbucks Foam and the Rise of Ambiguous Materials


Ten years ago, if you'd ordered a coffee anywhere in Britain, you would have found yourself looking down at a circle of watery brown liquid with a smattering of bubbles scattered over the surface. It looked as though someone had added a dash of detergent to dish water and then blown into it absent-mindedly through a straw. The advent of coffee chains, domestic and international, has entirely transformed the coffee drinking experience into a saturated, multilayered event. And the spiritual home of this luxurious super-foam is Starbucks, where the voluminous, airy froth tops your coffee plump and proud as a teddyboys quiff.

In fact it's hard to believe this stuff was ever as simple as milk. Only the faintly sour smell reassures you that it probably came out of a cow at some point in its history. Starbucks baristas have nicknamed the process that transforms it "Rock and Roll", derived from the action of knocking the stainless steel jug against the counter to dislodge air bubbles as the hot steam is pumped through the milk. Today the over-engineered machinery of coffee making is a contemporary fetish, the baroque complexities of the stainless-steel pipework and pressure gauges suggesting the mechanical thrust of a classic car plumbed into the artistry of a church organ.

The science of foaming involves, among other things, the speed, temperature and humidity of the steam; the nature of the nozzle; the shape of the jug; the fat content of the milk, and how the steam is introduced to it. Complex fluid dynamics combined with the physical properties of milk result in a precise quality of foam. This foam is milk that has been mechanically worked over, battered into assuming an entirely different quality. Generic natural milk becomes identifiable with a particular place, experience and brand--a product rather than ingredient--and also serves to justify the mark-up.
With a limited product range involved, intense competition magnifies the importance of each element: bean, roast, grind, and blend become significant points of difference between brands. This is the force that has driven steamed milk into such elaborate form. The significance of Starbucks foam is the embedding of brand identity into a natural phenomenon: lactate becomes logo.

Starbucks have dismantled, examined, and then reconstructed the coffee drinking experience. It's been reversed engineered to replicate flavour mug after mug, franchise after franchise, in amounts that could multiply until a river of coffee flowed into a caffeine sea.


Along with the thick, warm, smooth milky coffee that I'm slurping through my oversized beaker, I'm sucking up something else. Amongst all those soothing sensations there is a vaguely unsettling feeling. It's a feeling located intangibly between taste and the texture. I'm tasting things that aren't quite present, as though my Grande Latte is haunted by other materials. The milk is hallucinating un-milky attributes: a springy spawn with an easy, oily slickness, with a sweetness on the verge of vanishing within a numb plasticized volume. How did it get like this? What is it that has made it so ubiquitous, so quickly?


Steaming alters milk on a molecular level, breaking the chemical bonds within it and sweetening the taste by releasing lactose. It also increases the surface area of the liquid, increasing the sensation of taste. Water and milk fat form an emulsion that strengthens the bubbles skin. Foaming is now a staple technique in the avant guard kitchens of molecular gastronomy, a culinary movement that sees cooking recast as thermo-chemistry, where kitchen becomes laboratory and chef turns scientist. Michelin triple star chef Heston Blumenthal uses the effect at his restaurant, The Fat Duck, in Bray, Berkshire, UK, to heighten taste. His green tea sour mousse is sprayed as foam from a canister into a spoon, then dropped into a bowl of liquid nitrogen to instantly freeze the foam into a glob of high tech palate cleanser.

He is not the only chef to come up new ways of presenting flavors and texture. Ferran AdriĆ --head chef of the El Bulli Restaurant on the Costa Brava in Spain--has pioneered the concept of vegetable foams. AdriĆ  extrudes a mixture consisting of natural flavors mixed with a gelling agent such as agar--derived from the cell walls of some species of red algae or seaweed--through a whipped cream maker equipped with Nitrous Oxide cartridges. Out of this come delicacies such as foamed espresso, foamed mushroom, even foamed beetroot.


Foaming in these haute cuisine scenarios is a way of capturing taste like a purfumier captures scent. Both disciplines trap an essence then suspend it within a delivery mechanism that frames and articulates a precise experience. The chef and perfumier take elements of nature then filter it through culture. They refine primal, animal responses of taste and scent into highly crafted artifices. In these intricately foamed dishes, flavor takes precedence over the substance it is suspended in. Taste becomes divorced from its biological origin and amplified--a process that threatens to wring every drop of pleasure from nature.

Foaming is substance made less physical. The act introduces emptiness into the heart of a solid. There are gaps where there shouldn't be--like nights you can't remember because of binge blackouts, or holes in the fabric of life: bereavement, or heartbreak. A solid that is, in the words of the Buzzcocks Pete Shelly, "Hollow inside, we're all hollow inside/But I couldn't find out what the reason was/Why I was / Hollow inside". This is the existential echo that pervades my Starbucks latte.


Foaming is used to alter a wide variety of materials: rubber, polystyrene, concrete, aluminium, glass can all be foamed or aerated to extend the original material's qualities, delivering lighter, stronger, and more flexible substances, with greater insulating properties. From cosmetics to construction, edifice or edibles, you'll find them all around you, even if you might not see them. They're present in the spongy feeling when you walk in your high tech running shoes, the building envelope that insulates your home or office, the designed collapse of your car's bumper in mid-crash.

During the making of these substances, foam is created by inducing materials into a state of excitement. Once the foam has solidified the material's architecture has changed from solid to cellular structure. It is a frozen ephemeral state, where matter is held just on the right side of instability and collapse. The foaming process adds complexity to materials. They become more ambiguous in their structure and behaviour. And this ambiguity has a deeper undertone, suggesting that certainties can become unbound, that categories leak and bleed. Materials once gave grounding to the physical boundaries of human experience, but these boundaries are becoming blurred, hazy, untrustworthy.


"Particular foods were once considered as a single entity: an apple was an apple, a cabbage a cabbage and a pork chop a pork chop," writes Blumenthal. "Now, though, we know that an apple is, in fact, a recipe in itself, consisting of tens of thousands, even hundreds of thousands, of molecules, each contributing something to the texture, flavor or taste."

Unravelling nature is one thing. Repackaging it is quite another. When you put it back together, it turns into something very different.


Blumenthal's point echoes through modern design: traditionally, designers regarded materials as a kind of "found" truth that we inherited from nature--and thus both fundamental and essential. Stone, for example, was characterised as immovable foundation or tablet of moral truth. This attachment of meaning to physical stuff is fundamental to design culture. Maybe the old Modernists were right--maybe there is a morality to materials. Modernism found its medium in concrete, glass and steel. These materials reflected the circumstances of newly industrialized societies. They were used to express the idea that industrial production could create an idealized society. At the same time, they were a brutal snub to the stone used in bourgeois Beaux-Arts architecture, which attempted to connect to a set of classical ideals. Of course we now regard both classical and modernist ideals with distrust. We don't believe in the autocratic or aristocratic structuring of society and carry a growing ambivalence towards industrialization's social and environmental consequences. Perhaps the rise of foamed, ambiguous materials expresses our gnawing ambivilence.


The patron saint of aeration is Margaret Thatcher. In the 1950s, way before she entered politics, Thatcher was part of a team of chemists working for Lyons investigating methods for preserving the foamy quality of ice-cream. They experimented with injecting air into ice-cream until the point of collapse and found that substituting vegetable oil for the animal fat naturally occurring within the dairy cream improved the emulsifying quality of the mix. The improved ice-cream could hold more air, and long enough for it to freeze. This swirled up, foamy, frozen mixture of fat and sugar squirted out of machines as a premium product made with less material - an ingenious sleight of hand.

It is sorely tempting to draw parallels between Thatchers chemical and political legacies. And if one were to, perhaps one would be making comparisons with the atomisation of society, or perhaps one might speculate that Mr Whippy ice cream represented a proto- privatisation where air is transformed into commodity. One might even speculate that Thatchers chemical cue came from the Communist manifesto, where Marx argued that capitalisms transubstantive effect: 'all that is sold melts into air'. Perhaps Marx was staring at an ice cream as he struggled for the kind of linguistic imagery that would enthuse the proletariat.

Poet Wallace Stevens wrote "The only emperor is the emperor of ice-cream.' Perhaps he meant that grand political narratives could be played out through physical substance as much as through language.


Foam is a strangely liberated state: ephemeral, light-headed, almost intoxicated. It's stuff that has been agitated into an unnatural state that has escaped the confines of ordinary substance. In the spongy, stretchy, warm, super-strong foam we feel the sickening, trembling thrill of our time. This is the hyped-up sensation that both comforts and disgusts in equal measure as I slurp down my Grande Latte.


Posted by sam at April 28, 2007 10:10 PM


i've never thought about coffee and foam from this point of view.

Posted by:
Margherita on May 28, 2007 4:31 PM

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