The Fastest Coffee in the World

Before you judge, let me brief you on some important facts and provide a disclaimer:

This discussion pertains to espresso with milk only—not straight espresso. In the months leading up to the opening of Kirk’s new shop, I helped Barista Hustle organize a blind tasting together with Kirk, CEO of Barista Hustle Matt Perger, and the co-owners of Tortoise Espresso, Bronte and Lloyd Meadows. Our goal was to compare lattes made with fresh espresso and lattes made with 24-hour-old pre-batched espresso. Across 70 scorable samples, the pre-batched lattes received higher average rankings and more first-place votes than the samples madre with fresh espresso. Matt scored the pre-batched espresso and milk higher in every round.

A few weeks after this, Kirk received a visit from green buyer and founder of the celebrated US roastery Prodigal, Scott Rao. Kirk took the opportunity to set up a blind tasting to compare lattes made with fresh and pre-batched espresso. Scott’s first impressions were that the difference between the coffees was almost negligible. Then when Kirk pressed him to guess which was which, and to state a personal preference, Scott chose the pre-batched latte as his favourite, and he guessed that it was the fresh sample. If that doesn't persuade you of the potential for making lattes with pre-batched espresso, I’ve got one last piece of evidence:

A few years back, when I was running the London Barista Resource at Prufrock, we had a debate about how long it was acceptable to keep an espresso sitting on the bar before pouring milk into it, lest it develop oxidized flavours or lose aromatic intensity. We organized a blind tasting with all of Prufrock’s baristas, comparing a freshly lattes made with one-hour-old espresso and fresh espresso respectively. We were careful to make both lattes at exactly the same temperature, knowing the pre-batched shot would be cold, and to serve them without any latte art so the visual difference wouldn’t be discernible. Of the Prufrock staff, all preferred the one-hour-old to the fresh. So whatever side of this debate you fall on, you need to know: there is mounting evidence that pre-batching espresso has the potential to improve the flavour of lattes. And then there’s the blistering speed of service to consider.

Making a latte from start to finish in 15 seconds is three times faster than Starbucks’s typical output. Their Thermoplan Mastrena super-automatic espresso machines typically take 45 seconds to produce a single-shot latte. It’s also a lot faster than outfits using hybrid-automatic machines like the Eversys Cameo, which can make 175 shots of espresso per hour, which sounds mighty impressive—just over 20 seconds per shot. In Project Zero, the shots are volumetrically dosed in under three seconds. As a barista, I can’t help feeling smug that expensive Swiss automation in the hands of mass coffee chains is being outpaced by an independent Melbourne cafe.

Last year during the Melbourne International Coffee Festival, Barista Hustle organized a public debate in light of the 10,000 vacant barista positions across the country. Since then, the Melbourne coffee scene has become knee-deep in automation. In Melbourne, it’s rare not to see an Uber milk or a La Marzocco Wally on the bar. These machines both heat and aerate the milk. There are a few owner-operated cafes I frequent that use traditional equipment, and I know their owners would love a super-automatic espresso machine to magically appear on the bar every time they're short-staffed. They just don’t have the capital to change out their traditional espresso machines for a super-auto, or to keep a spare Cameo for emergencies. But having witnessed the potential of pre-batched espresso and milk, where the espresso was prepared on a ‘traditional’ machine just a few hours earlier, I know what I would do during a staffing crisis. If, for instance, I was managing a busy inner-city cafe and I got the call from a barista saying ‘I’m not going to be able to make it in today,’ I would turn up half an hour early, pull a few dozen shots into a tasteful-looking sauce bottle and start dosing those shots into lattes the moment I noticed my short-staffing problem was running regulars late for work.

Of course, pre-batched espresso is not new. In the 1880s, Moriondo was selling long necks of pre-batched black coffee made on a huge pressurized coffee maker many consider to be the first espresso machine. In the 1990s, you’d always see half a dozen pre-made espresso shots sitting on the drip tray of a busy coffee shop, waiting to become cappuccinos. The difference is, until now, pre-batching has been done by subterfuge. Even Kirk, when he started piloting the idea, was doing it covertly—keeping the espresso in a sauce bottle, dosing it on a scale, all shielded from view behind a three-group Linea PB. What’s different and better about the new system is that it’s unapologetic. The queues keep growing—or at least they would if folks weren’t having their orders fulfilled half a minute after stepping through the door. According to Kirk, no one who has actually tasted his coffee—which rules out nearly everyone who has disparaged Project Zero on Instagram—has noticed any degradation of flavour, even when the pre-batched espresso is up to four days old, which is Kirk’s recommended ‘best before’ date.

A pickering foam

At Barista Hustle, we wanted to find out if there’s a scientific explanation for why pre-batched espresso could outperform fresh espresso when it’s combined with freshly steamed milk. We had a feeling the difference lay in the presence of crema on a fresh shot, and the fact that the crema has completely dissipated in a pre-batched shot, so we ran the question past Dr Anja Rahn, coffee researcher at the Department of Food Science and Agricultural Chemistry at McGill University:

A big surprise during this test was that whisking pre-batched espresso caused rapid Ostwald ripening. You’ve seen Ostwald ripening before if you’ve accidentally jetted some air into your milk late in the steaming process. The difference in internal pressure between small and large bubbles causes gas to diffuse out of the small bubbles and into the larger ones. The small bubbles gradually vanish while the large bubbles grow, progressively giving you a less creamy texture with every passing second—amazing to watch, but destructive to the beverage’s mouthfeel.

But here’s a twist: Multidisciplinary coffee scientist Professor Steven Abbott was actually very surprised that the pre-batched foam ripened so quickly.

Prof Abbott then gave us his theory on why espresso crema lasts longer than it should, and why it could be responsible for imparting a slightly acrid taste to a freshly poured latte:

As he explained, in a normal foam, bubbles are stabilized by surface-active molecules or ‘surfactants’, e.g., proteins, lipids, and detergents. But in a Pickering foam, tiny solid particles lodge themselves at the air–liquid interface. Once there, they are energetically difficult to remove, creating—at least temporarily in the case of crema—a mechanically robust bubble wall. If Prof Abbott’s theory about crema is correct and espresso crema is a ‘Pickering foam’, why doesn’t it apply when you foam up pre-batched espresso? Here’s how he explained that one, with the help of a champagne analogy:

So there’s the scientific explanation. It suggests to anyone considering prebatching that they should not try to add crema back into the equation. And it explains why espresso ‘senza crema’, where the crema is removed, can sometimes taste nicer than a normal shot.

Given how well pre-batched espresso performs with milk, and the benefits of having a crema-free liquid with which to construct a latte, you’d think there’d be scope for serving pre-batched shots of espresso too. If you like iced espresso, then yes. But at present, we’ve not encountered any successful means of reheating the liquid in a way that doesn’t cause rapid degassing and flavour loss. At Project Zero, if you order an espresso or a long black, your shots are made fresh to order.

Is pre-batched espresso fast food?

What would Carlo Petrini, founder of the Slow Food movement, say about the fastest coffee in the world? The movement formed in the ’80s as a response to McDonald’s building a restaurant at the bottom of the Spanish Steps in Rome. Here’s the opening paragraph of their manifesto:

In the Slow Food manifesto, they make a few practical suggestions that could help us work out where pre-batched espresso leaves ‘specialty coffee’ as a movement: ‘Begin by cultivating taste, rather than impoverishing it, by stimulating progress […] by endorsing worthwhile projects.’ Their last recommendation is that we should ‘[advocate] historical food culture and [defend] old-fashioned food traditions.’ All espresso could be considered fast food when viewed through the Slow Food lens, and yet, thanks to Kirk, I’m starting to use the term 'traditional espresso’.

I’ve got a feeling Carlo might be into Project Zero’s approach. The Slow Food movement was never really about how long something takes to prepare—it was about protecting flavour, craft, and culinary culture from the flattening effects of industrialization. If a technique demonstrably improves flavour, then according to the manifesto, it is ‘stimulating progress’ rather than impoverishing taste.

What’s striking about Project Zero is that it achieves its speed without surrendering any of the values that specialty coffee claims to uphold. The espresso is still dialled in by a barista; the beans are still sourced and roasted with the same level of scrutiny; the only difference is that the liquid is allowed to sit for a while before being combined with milk—and as our tastings suggest, that slowness improves the flavour.

Project Zero’s approach feels less like fast food and more like another example of the long, strange evolution of espresso itself. After all, the original espresso machines of Moriondo and Bezzera were invented precisely to make coffee faster. Every major innovation in espresso—pressurized extraction, spring levers, pump machines—was designed to speed things up. And yet we don’t consider espresso the enemy of flavour; we consider it a craft.

Project Zero’s speed, then, might be less of a provocation than it first appears. It isn’t the result of industrial shortcuts or automation. It’s simply what happens when a barista realizes that a good ingredient sometimes benefits from a little slow-down before it’s served. The latte just happens to arrive 15 seconds later.

And if that’s the fastest coffee in the world, it may also be one of the most quietly slow.