Espresso grinders come in two flavours – those with a doser (a lever on a coffee grinder that dispenses [‘doses’] the ground beans), and those that are doser-less. Grinders with dosers were designed so that batches of coffee could be ground all at once, then portioned into a portafilter (the handled part of an espresso machine that holds the filter basket, into which ground coffee is placed) when an order was placed. You’ll recognize them as the grinders that have a paddle or lever on the side. Obviously this is not good practice, as ground coffee should never be left to sit for more than minute or so. On the face of it, the doser-less grinder would appear to be the best choice, since it has fewer moving parts and fewer places to trap coffee grounds, as well as enabling the ground coffee finds its way straight into the portafilter basket ready for brewing. However, many grinders with dosers are now equipped with timers that grind the perfect weight of coffee to order, and the barista can dose repeatedly until the dosing chamber is empty of grounds. For some this is a preferred choice, since the doser does a neat job of depositing grounds into the filter basket, as well as the fact that doser-less grinders have a tendency to spit coffee grounds out in a devil-may-care fashion, which is both a messy and inaccurate way of operating. As with many things, a lot of it comes down to personal preference.
For modern espresso grinders the dose is calibrated by a digital timer that can be set to grind for a specific period of time. Logic would tell us that this would equate to a consistent weight of coffee regardless of how coarse or fine the grinder is set. This is not the case, however, as the finer the grind gets, the slower the output of coffee (the burrs have more work to do), meaning that the adjustments are relative to one another. We are beginning to see a new breed of grinder that aims to overcome this by automatically compensating for a change in grind fineness. In the future, I hope to see espresso grinders that dose by weight, but the mechanics of such a thing are difficult to imagine, let alone engineer.
Another problem that grinder manufacturers are having slightly more success in dealing with, but one that will likely never be truly overcome, is ground coffee retention. The pathway from the burr set to where the grounds are dispensed has long been a hiding place for stray grounds to convene, and minimizing the length of this transition along with its bias for catching grounds is the focus of many new grinder designs. From a dosing perspective, this causes only minimal bother, since the pathway is likely to hold a fairly consistent mass of coffee. From the perspective of dialling in the grinder, it does present a problem, though, as the grinder must be purged of any old grounds after making adjustments, to avoid inconsistency.
Commercial grinders intended for processing filter coffee are usually much bigger and more powerful than espresso grinders. They also tend to feature larger burr sets, meaning that they can process coffee quicker without the burrs overheating. These grinders are most effective when fed with the desired weight of coffee before being set to grind until they are empty.
Grinders need to be cleaned from time to time in order to remove stale coffee oils and to keep the grind time to a minimum. You can open up the machine, remove the burrs and clean them with a toothbrush, but a much easier method is to let the grinder chew on grinder cleaning pellets. These coffee-bean-sized nuggets manicure your burrs and scrub away oils and debris. I recommend putting 50 g/1¾ oz through for every 10 kg/22 lbs of coffee.
A perfectly formed stream of finely ground coffee falls from the doser of a top-end Mazzer espresso grinder.
06
ESPRESSO
INTRODUCTION
Ten years ago, it would have been easy to convince the average consumer that espresso (and drinks based around the espresso) is the only acceptable way to drink coffee when out of the home. It was true, after all, that espresso was riding a 50-year rolling wave of domination, shaping the coffee shops of the Western world and beyond. Indeed, when I first learned how to make good coffee I held the strong belief that coffee prepared any other way simply would not do. Baristas were generally in agreement that big, watery cups of black coffee with – heaven forbid! – absolutely no crema (see pages 96–97) were an altogether inferior product. I do look back on those days of pursuing the ‘god shot’ with a great sense of nostalgia, though, and it’s with a sense of focused enthusiasm that I hope to discuss the subject with you, dear reader.
And focus is as good a place to start as any, since that’s what espresso is really: finely ground coffee and pressurized hot water, served in concentrated form. I once heard Stephen Morrissey, the 2008 World Barista Champion, describe making an espresso as ‘like looking at coffee through a magnifying glass’. I personally liken it to watching cars race through a pair of binoculars, where mastering the difficult job of following a fast-moving object will reward you with excellent clarity of the spectacle – the downside being the apparent ease with which you can miss the mark entirely.
A shot of espresso is an honest and unforgiving thing. It celebrates attention to detail by highlighting what may be excellent about a coffee, and laughs at your bad practices by tasting intensely bad. The variables may seem a small set – grind size, dosage, extraction time and beverage weight, but the margin for error is enormous. Even when all the variables are fixed through a complex balancing act, an espresso machine and grinder can still produce unexpected results and coffee that ends up down the drain.
Why then, do we bother? Wouldn’t it be easier if every café just made a big pot of coffee in the morning to last the whole day? Well, part of the allure is perhaps the seemingly endless customization of the espresso that has fostered our enduring love of the espresso bar. The simple mixture of water, coffee and milk can be bought and savoured in a remarkable range of styles and options these days and we will discuss some of these in the following section (pages 100– 111).
Then, there is the freshly made convenience of the whole thing. It takes little more than 30 seconds to extract an espresso, which is a great deal quicker than any other brewing method in this book. The ritual of the barista comes into this, too. Like an engine driver mastering an infernal machine, the barista moves around with practised grace – his or her actions punctuated by a sharp hisses of the steam and a low whirr of the pump. The espresso machine is an icon of the modern café, and indeed, modern life, as much a part of the coffee shop as the beer font is to the bar.
The iconic Italian espresso with its characteristic crema crown.
THE HISTORY OF THE ESPRESSO MACHINE
To better understand how the espresso machine works and what it does, we must ask ourselves why it was needed. Before the espresso machine appeared, coffee brewing was more often than not a lengthy process. Not unlike the cafés of today, people weren’t at all impressed with having to wait around for something that they believed should be made available very quickly. As a result of this, the common practice in coffee shops was to brew in bulk, then either reheat, or hold the coffee over a heat source, dishing it out on demand to those awaiting their caffeine fix. Today, there are many modern pieces of equipment that satisfy this demand in a highly effective manner – though none so quickly as the espresso machine. However, in the early 20th century it meant stewed, overextracted, and insipid cups of black soot.
The only effective solution would be a brewer that could make a single cup in under a minute, over and over again. And the only way to brew coffee very quickly is to grind it much finer, increasing the surface area of the coffee grounds and therefore the contact with the brewing water. Finer grounds meant that less water was required for proper extraction, but this posed its own problems when it came to filtering the coffee back out of the liquid, since the particles of coffee were so small. A very fine filter would go some way towards solving this, but it didn’t address the problem of percolation, where gravity alone would not be sufficient to make the water pass through such a tight package of grounds. The only solution was pressure. By pressurizing the brewing water, the coffee could be ground much finer still, and in itself form a restrictive
barrier for the water to pass through. As such, paper and cloth filters were out of the question, since they wouldn’t be capable of withstanding the forces at play. If the water pressure remained constant, the rate of extraction could be adjusted by changing the fineness of the grind and the dose of the coffee.
Although some espresso machines can now have their pressure adjusted, it is ‘9 bar’ (nine times the pressure exerted by the earth’s own atmosphere) that was the number that was finally settled upon. To put it another way, imagine a 90-m/300-ft pipe protruding vertically out of the top of an espresso machine, and that pipe being filled to the top with near-boiling water. That is the kind of force exerted by an espresso machine today.
STEAM POWER
It was the late 19th century and Europe’s near-100-year love of everything steam-powered continued to puff along. Manufacturing a near-instant pressurized coffee brewer in the 19th century was not at all easy, though. Glass and metal components were not produced in the style of modern manufacturing methods, and when placed under high pressure, explosions were frighteningly commonplace.
The earliest design for a precursor to an espresso machine that I have come across is from a patent filed in 1878 by the not-very-Italian-sounding Gustav Kessel (he was German). Kessel’s machine used steam pressure to force water through a small bed of coffee and even produced a blast of steam at the end to dry the ‘puck’ of spent coffee for easy removal. It produced a single-serve beverage, quickly and efficiently, but there was one major flaw: it was impossible to build.
It was another six years before a machine similar to Kessel’s contraption was actually built. Although all we have to go on is an old patent for its design, it was an Italian entrepreneur by the name of Angelo Moriondo who, in 1884, presented a working example of his ‘new steam machinery for the economic and instantaneous confection of coffee beverage’ at the Turin General Exposition. This early steam-driven espresso machine worked in a similar fashion to the Pumping Percolator of the early 1820s, by using steam pressure to force water through a bed of coffee. Moriondo’s machine was a much more serious piece of bar-top kit, however, and undoubtedly the earliest-known machine that controlled steam and water in two independent boilers – a hallmark of the modern espresso machine. But despite all that, Moriondo’s machine did not produce single-serve espresso as we know it; it was effectively a bulk brewer that operated at a faster rate than normal – perhaps that was why he only won a bronze medal at the General Exposition. Moriondo guarded his invention jealously, though, tinkering with the design over the years following its unveiling and manufacturing only a handful of the machines for his own stores. Sadly, there are no known confirmed examples of Moriondo machines still in existence today.
The world would have to wait until 1901 for the first commercially manufactured single-serve coffee maker, and a further two years for all the teething issues to be ironed out. It was the concerted efforts of two men, Luigi Bezzera and Desiderio Pavoni (respectively the Steve Wozniak and Steve Jobs of the Italian coffee movement), who made espresso a reality. It started with Bezzera, the ideas man. Bezzera’s design for his ‘Giant type with double tap’ was the first to use a portafilter; it was also controlled using levers, and included options for multiple brew heads. The only downside was the fact that it was heated over an open flame. Bezzera successfully built his machine, but like so many other inventors, he lacked the marketing skill to roll it out.
Enter Pavoni. In 1903, Pavoni reportedly paid 10,000 Italian lira to Bezzera for his patent, recognizing immediately the potential for such a machine, and the pair began to work on the project together. Pavoni was more than just a marketeer, however. He introduced a couple of tweaks to Bezzera’s original design, namely a pressure-release valve that directed some of the steam away from the barista, and more importantly – or perhaps less so if you’re a barista being blasted with a jet of hot steam – a steam wand that could effectively target some of the machine’s stored-up resources to create a useful tool for heating up milk.
They called the coffee it made ‘cafeé espresso’ as it was made quickly and on the spur of the moment, and the finished machine, called the Ideale, was presented at the Milan Fair in 1906. The Ideale was fast, but like other steam-powered machines, it could only generate a pressure of 1.5 bar – slightly above that of a home pressure cooker. This pressure wouldn’t be possible to produce the level of concentration that a modern shot possesses and by current standards this was not espresso coffee.
Over the following 40 years, Pavoni and Bezzerra’s design remained relatively unchanged. Other companies began producing similar steampowered machines, but very few left Italian shores and even within Italy, they were not as commonplace as you might imagine. It took the arrival of coffee guru Pier Teresio Arduino to make that happen. Arduino began developing his own espresso machine around the same time as Bezzera and Pavoni, but his contribution to coffee was more in the marketing of the espresso than the evolution of the machine. The most well-known example of this, and perhaps the most famous piece of espresso-related marketing of all time, is a piece of 1922 Victoria Arduino Company advertising that depicts a yellow-jacketed man grabbing an espresso from a moving train. Arduino made espresso machines sexy, and early examples of his machines can still be found all over Italy today, instantly recognizable by the eagle that adorns the top.
PISTON DESIGNS
Arduino also explored the idea of using a piston operated by a mechanical screw to generate more pressure. So too did Marco Cremonese, an inventor who, in the 1930s published detailed and wide-ranging patents that covered all kinds of espresso machines that used mechanical pistons to generate pressure in place of steam. When he died in 1936, his wife, Rosetta Scosa, attempted to license her husband’s designs to various different manufacturers, but to no avail.
One of those men was the Milanese café owner and all-round tinkerer Giovanni Achille Gaggia. Gaggia filed a patent in 1938 for his own ‘Rotative screw piston’ coffee machine and even modified a few machines to incorporate it. World War II halted further development for Gaggia, then after the war ended, his endeavours awarded him a law suit from Cremonese’s widow, who successfully sued Gaggia for patent infringement. By this point, after nearly ten years of perseverance and significant cost, Gaggia had become disenchanted by the basic design and reliability of the screw piston. He went back to the drawing board and began working on a new design that did away with screw pistons altogether. And we’re all glad that he did, because his next creation would be the first machine to produce the espresso that we all know and love.
Gaggia’s eureka moment was in the development of his spring piston mechanism, which solved the mechanical problems associated with the screw. Gaggia’s idea was to use a hand-operated lever to compress, or cock, a spring, then once the lever was released, the enormous tension in the spring causes it to expand, forcing the piston down and pushing hot water out of the chamber and through a bed of finely ground coffee.
Stiffer springs meant higher pressure, which meant finer coffee; this, in turn, meant faster, smaller drinks. In 1947, Gaggia had a working prototype of a coffee machine, the first machine recognizable as a modern-day espresso machine. Crucially, the machine operated at pressures much higher than anything that had come before. The massive force exerted by the machines resulted in a more viscous, dense and treacly type of coffee. Furthermore, it produced a layer of brown coffee cream on top of the drink, subsequently named ‘crema’. His invention, not to mention the remarkable resulting coffee, was so monumental and radically unique that people literally couldn’t believe what they were seeing and tasting.
It is no exaggeration to state that Gaggia espresso machines changed everything in the coffee world. Here is one of the company’s earliest models.
A nearly new, copper-clad Victoria Arduino espresso machine on an Italian bar top.
THE ELECTRIC PUMP
Lever machines like Gaggia’s are still in operation in many cafés around the world; in fa
ct, some cafés still use lever machines, preferring the benefit of control that they offer. But there was one more milestone in the development of espresso machine design and that arrived in 1961, with the introduction of the Faema E61, invented by Ernesto Valente. The E61 was revolutionary for a number of reasons, but most notably for its electric pump, which meant no more pistons, no more reliance on the manual force of the barista, and a much smaller machine. The pump heated tap/faucet water through a heat-exchange coil inside the boiler before directing it into the group head. In addition to this innovation, the machine also circulated hot water from the boiler through the group head continuously, to better stabilize the temperature of the machine.
HOW AN ESPRESSO MACHINE WORKS
Since the middle of the 20th century, boilers, digital thermostats, pressure management and aesthetics have advanced significantly, but in many ways the espresso machine is quite unchanged from the 1960s, and as such, can be a little inconsistent. One thing that is consistent among all espresso machines, though, is the need to pressurize water for coffee brewing. The most basic way of achieving this is still with a lever-driven piston that forces water through a bed of coffee. Some levers use a spring mechanism (see page 89), while others require arm power to generate pressure to drive water down through finely ground coffee. It goes without saying that while a manual lever might offer infinite pressure-profiling possibilities and a certain romance to its operation, they do tend to have a somewhat mercurial temperament about them.
The Curious Barista's Guide to Coffee Page 12