Whilst my favourite brew methods are all manual (particularly filter – my favourite of which is the Costa Rican Vandala) the truth is, without espresso machines cafes would go broke. Without all those lattes, flat whites, cappuccinos, piccolos, short blacks and macchiatos, coffee shop life would be more than hard, it would fall apart. Plus, espresso machines are beautiful.
What is espresso?
Before we can discuss the history of espresso machines, it’s worth defining what espresso actually is. There are a few different definitions – but to summarise the standard SCA definition, it’s a 25-35 ml beverage prepared from 7 to 9 grams of coffee (14 – 18 grams for a double, which is what we consider standard in Australia). The water temperature should be 90 to 96 degrees Celsius and the grind of the coffee making the brew time 20 to 30 seconds. While brewing, the coffee will appear to have the gooeyness of warm honey, and finish with a thick dark golden crema. Espresso should be drunk immediately after brewing.
But the single most defining characteristic of espresso compared to other brew types is pressure. That’s what’s creating that crema and it’s what’s allowing so much of the flavours of the coffee to be extracted using so little water and in such a short amount of time.
So with that out of the way, let’s talk history.
Angelo Moriondo’s steam pressure
In 1884, Angelo Moriondo was granted a patent for a coffee machine that used steam pressure to brew coffee and this is often referenced as the first ever espresso machine, but there are a couple of problems with this attribution. It’s true that it was a machine that brewed coffee with pressure from steam, and of course pressure is a key ingredient to brewing espresso, but it was more of a batch brewer than a single serve coffee machine. Plus it was never really produced at scale. It never became popular and there really weren’t many of them.
Luigi Bezzerra’s portafilter
But in 1901 things in Milan were starting to get more interesting. A mechanic called Luigi Bezzerra made some improvements to this style of machine. He added the portafilter and had multiple group heads so you could brew multiple coffees at once. So now, it wasn’t a batch brewer. However it still used steam pressure to brew the coffee.
Desiderio Pavoni’s release valve and steam wand
Then just a couple of years later in 1903, inventor Desiderio Pavoni came along and bought a bunch of existing patents and worked to popularise this style of machine. He made a couple of improvements that these days are considered standard, such as the first ever pressure release valve and the first steam wand. So now milk could be heated up from the excess steam in the machine.
But we’re still not quite there yet
During this time is when we first see the term Café Espresso emerge. But even though our characters in this tale so far made some substantial improvements on the previous versions of the machine, there are still some fundamental issues with it. A big problem with these machines was that they were still using steam to brew the coffee. As we know, that is way too hot for most people’s taste preferences – you’re burning the coffee. But the most defining weakness is that it had really limited brewing pressure – the most these machines could use was about 2 bar (compared to 9 bar currently standard). This meant that there was no crema - there was not enough pressure to pull out that delicious oily structure that sits on top of the coffee.
So up until this point we don’t have enough pressure, which as you’ll remember from the introduction, is the most defining characteristic of espresso.
Introducing… Achille Gaggia’s lever
In 1947 this changed. Enter the Gaggia Spring Piston Lever. In Milan, a machine was developed by Achille Gaggia that used hot water pressure instead of steam pressure, and this is the first time we see that beautiful golden crema on top of the coffee. The machine used a lever to firstly compress a spring and draw water into a brew chamber directly above the puck of coffee. Then when you release the lever a wall of water get forced through the coffee at high pressure by the spring. And the result is an espresso shot that closely resembles what you are likely to see in cafes today. And so the Gaggia Spring Piston Lever is what could reasonably described as the first espresso machine, although it was standing on the shoulders of giants.
One key thing to note with this machine compared to the modern expensive lever machines sometimes sold for home use is that the lever is first compressing a spring and then the water is forced through as it is released. In today's home use machines you are actually forcing the water through the puck as you pull the lever.
Heat exchange vs dual boilers
Before we continue forward towards the present day, we need to discuss the difference between heat exchange machines and dual boiler machines.
Heat exchange machines
Heat exchange machines have one boiler in them and that has to be hot enough to power the steam wand. The boiling point of water actually increases under pressure, so what you’ve got is water that’s really hot, and as we discussed earlier, that’s not a good temperature to be brewing coffee with (for most people’s taste, but, you know, please yourself if you feel differently).
So what a heat exchanger does is it takes water into a thin copper pipe that coils around in the boiler. The water in the pipe is then heated up as it goes through the pipe and gets pumped into the group head. As you change the frequency of how often you are pulling shots, the water temperature in the pipe is changing. If the water in the pipe has been sitting there for 5 minutes, then it’s basically as hot as the water in the boiler – which is too hot.
To correct for this, you can do this thing called temperature surfing, which is where you have a purging routine depending on how much the machine is being used. By purging the water from the pipe before pulling a shot you are able to stabilise the temperature of the water coming through and improve consistency.
Dual boiler machines
The other option is dual boiler machines, which are much simpler to understand and are exactly what the name implies. They have one boiler for the coffee and another boiler for the steam wand, and each one heats the water to the appropriate temperature for their purpose. This makes them much easier to get consistent coffees from.
Ernesto Valente’s pump
Now, back to the history of espresso machines. It’s 1961 and we’re still in Milan. This is the time and birthplace of one of the most famous things in espresso – the e61 - invented by Ernesto Valente. The thing that made this really special is that he developed the first pump driven espresso machine that delivered 9 bar of pressure. This is the classic espresso machine and you can still get them today. It is a heat exchange machine, and this was the king of espresso machines for many years. Until…
La Marzocco’s dual boiler
In 1970 La Marzocco introduced something that forever changed espresso machines. They made the first dual boiler espresso machine - the La Marzocco GS - and featured saturated groups (“GS” stands for “gruppo saturo”). As well as independent boilers, the brew groups were attached directly to the boiler and were designed to create a chamber for water to circulate continuously.
The dual boiler already dramatically improved stability, but by having saturated groups you got a lot more temperature stability than anything else that’s ever been around. Temperature stability improvement started with getting away from using steam, then by using a heat exchanger, then by using multiple boilers and saturated groups.
We’re now in the modern world of espresso machines. But improvements aren’t over yet. One of the improvements since 1970 is using a static water tank plumbed inline with the espresso machine, which heats up the water before it enters the boiler, and this reduces the time it takes to get the boiler back up to temperature after each shot is poured.
Then there’s PID technology.
And individual pressure levels for different group heads.
And pressure profiling.
And a whole bunch of technology that I’m nowhere near qualified to discuss. If you want to tech-out on the latest improvements, head into a specialty coffee equipment shop and get the lowdown.
One thing is for sure - improvements aren’t over yet. Improvements in freshly roasted coffee beans have also improved by leaps and bounds in recent years. The biggest improvement has been direct access to roasters via coffee subscriptions. Getting the perfect coffee subscription is a story for another post though.
Written with input from members of the Coffee Geek community.