Introducing the Gaggia Achille


Over the years the lever espresso machine has caught many an espresso fanatics fancy. The lever machines elegant design, its unique shot properties and the Zen of being one with the extraction process. You see, in order to pull a good lever machine shot you have to live in that moment; nothing else matters for that brief 30 seconds of joy.

Most home lever machines are based on either gravity fed groups (La Peppina) or pressure fed groups (La Pavoni Europiccola and Elektra Microcasa a Leva). The latter type of lever espresso machines rely on steam pressure to push the boiler water up a group feed tube and into the group piston chamber. In order for that to work, the boiler must be at pressure. The minimum pressure required is about 0.6 bar, which correlates to a water temperature of around 235F. Due to those high temperatures, most lever machines with this design overheat after the third or fourth shot, turning that 30 seconds of joy into 30 seconds of bitterness as your espresso burns from the high water temperatures.

Gaggia has introduced the market to the Achille - a lever operated heat exchanger espresso machine. The heat exchanger design does away with the overheated lever espresso machine and has the potential to pull shots of espresso all day long.

Does this evolutionary design live up to the potential and its $1300 price tag? Join me as I research the new Gaggia Achille, sponsored by Whole Latte Love.

Lever Espresso Machine - What is the big deal?

For those of you that are not members of the Lever Machine World Domination Plot (LMWDP), a bit of lever machine history and operational overview may help you to understand the passion these machines evoke.

Back in the late 1800 to early 1900's, the first pressure brewing methods were emerging. These pressurized percolators earned the moniker of 'espresso brewed coffee' due to the reduced percolation time and individual serving capability. The coffee was brewed 'expressly for you' one cup at a time. These early espresso brewers used steam to generate the brewing pressure. Unfortunately, that steam not only accelerated the percolation of coffee but burnt the coffee due to the high temperatures and direct contact of steam with the coffee grounds.

In the 1930's Sr. Cremonese patented the screw piston mechanism. This allowed for manual pressurization of the percolation group. The high pressure steam no longer came in contact with the ground coffee which greatly improved the taste of the coffee. In 1938 Achille Gaggia applied for a patent for the rotative screw piston group.

Mr. Gaggia never perfected the screw piston group. The design, while an improvement on the older steam pressure machines, still had many mechanical flaws. His next idea was to use a spring powered vertical driven piston. The spring would provide constant pressure to the group piston. Achille Gaggia discovered that using a consistent and fine grind in conjunction with the spring powered piston he could percolate a 'short black' in 15 seconds. The increased pressure also created a reddish brown froth; crema was born. On August 8, 1947 the spring assisted 'espresso machine' was patented, laying the foundation for what we now call espresso.

Lever espresso machines harken back to that original spring piston design of Achille Gaggia. While the modern day pump driven machine is easier to use, it loses that Old World charm. You do not purchase a lever espresso machine to produce a hassle free drink. You purchase one to become one with the process. The machine must become an extension of yourself and for that brief moment you are reconnected with history.

Avidly awaiting basket dimensions and shapes, water-volume dispensed by single pull, piston diameter, and whether or not flushing is necessary, and if so, how much? Also, what is the coolest brew temperature the machine will support (while still producing ample steam) and for how many shots in succession?

Regards
Timo

P.S. Lever/fulcrum dimensions also appreciated! Length of arm, distance between pins (on-center).

In the works. I can't give away all of the goodies at once. The first couple of sections will be somewhat bland to the LMWDP membership but necessary for the first timers to the lever world.

I will make sure I get your requested information.

cannonfodder wrote:In the works. I can't give away all of the goodies at once. The first couple of sections will be somewhat bland to the LMWDP membership but necessary for the first timers to the lever world.

You envision part I to be a general introduction to how levers work?

cannonfodder wrote:I will make sure I get your requested information.

Thanks. I would really like to have your direct observations rather than something culled from the marketing literature or told to you by the marketing folks, especially in terms of my question about the coolest temperature possible for brew water and inter-shot temperature stability. Inter-shot temperature stability is supposedly what sets this machine apart from other levers currently on the market, so I hope temp stability will be the centerpiece of your review.

Regards
Timo

Yes, that is the base for the first section.

No marketing, all me and HB. You will get both the highs and lows of the machine uninfluenced by the manufacturer or sponsor. The detailed thermometry will have to wait for Dan. I don't have a data log thermocouple, but rest assured, it is in the works. My measurements will be based on what I taste in the cup.

Modern Day Lever Espresso Machines

Modern day lever piston espresso machines use three different water supply brew systems and two different piston power designs.

Spring assist and manual lever.

There are two different piston powered systems. The spring assisted lever uses a coiled spring to regulate the extraction pressure of the piston. When the lever is depressed, the piston is cocked. You simply release the lever and the spring delivers the needed pressure for your extraction. The Elektra Microcasa a Leva is one of the most popular spring assisted lever machines.

The second power system is, well, you. The full manual lever relies on the operator to supply the needed pressure to the lever for extraction. These systems require much more time to learn. The operator has to apply steady pressure to the lever during the extraction. The difficult part is training yourself to apply the same amount of pressure for every shot. The La Pavoni Europiccola and the Gaggia Achille are two of these full manual systems.

Water delivery methods.

The most common type of water delivery is the steam pressure driven. In these systems, a single large boiler supplies both brew water and steam power. The machine relies on steam pressure to force water up a brew group supply line and into the group piston chamber. In order for that to work, the water in the boiler must be hot enough to generate steam. Most of these machines operate around .8 bar, or roughly 250F.


Hydraulics diagram from the Olympia Cremina manual

Since the brew water is well beyond the target brew range (195-205F) the water must be cooled prior to the extraction. On these machines, the group acts as a heat sink, leaching heat from the brew water as it enters the piston chamber. This is not a good way to regulate the brew water. Every time you pull a shot, the group absorbs more heat. Most of these will only allow for 3-4 shots before they overheat. Extended idle time also results in an overheated group because the grouphead is directly attached to the boiler. Common machines in this category include the La Pavoni Europiccola, Olympia Cremina and Elektra Microcasa a Leva.

Gravity feed (open boiler) water delivery systems can avoid these overheating problems. A gravity system uses a boiler placed above the grouphead. When the lever is lifted, gravity pulls the water down into the group piston. Because steam pressure is not required to move the water, these systems can operate at much lower temperatures. The water in the boiler can be kept at or slightly above the target percolation temperature. The disadvantage of these systems are two fold:

1. Because the boiler is located above the grouphead, most of the machines mass is located high off the counter. That tends to make them a bit top-heavy and prone to tipping over if the base is not sufficiently large.
2. These systems generally have one boiler, the brew boiler. Because these are run at brew temperatures, there is no steam for creating milk drinks.

The La Peppina and Mini Gaggia/Minimoka are popular gravity fed open boiler machines.

Heat exchanger is the third water delivery method. A heat exchanger uses a high pressure (usually 1 bar and up) boiler with a brew water supply line running through it. Most commercial lever machines use a large steam boiler with one heat exchanger per group supplying brew water. As the cold water passes through the heat exchanger tube it is flash heated to brew temperature. The resulting brew water can be adjusted up and down in temperature by the dwell time. The longer the water sits in the heat exchanger, the hotter it gets. The majority of commercial machines use a heat exchanger system. Below is a heat exchanger hydraulics diagram for a pump-driven espresso machine:


For more on how a heat exchanger works see Espresso Machines 202

Commercial lever heat exchanger machines are plumbed into a water supply. The lever machine's heat exchanger uses the mains water pressure to force the brew water through the heat exchanger and into the brew group. This system gives the barista much more control over the brew water temperature. In the event the grouphead overheats, the barista can cool the unit by pulling a long flush of cool water through the group. These machines are intended for all day use. Our Gaggia Achille lever uses this same principle to overcome the inherent overheating problems of the steam pressure driven systems while still providing steam for milk based drinks.

So the question is, can the Gaggia Achille run all day like a commercial heat exchanger without overheating? Over the next few days, I plan to answer that question.

cannonfodder wrote:Yes, that is the base for the first section.

No marketing, all me and HB. You will get both the highs and lows of the machine uninfluenced by the manufacturer or sponsor. The detailed thermometry will have to wait for Dan. I don't have a data log thermocouple, but rest assured, it is in the works. My measurements will be based on what I taste in the cup.

perfectamundo

cannonfodder wrote:So the question is, can the Gaggia Achille run all day like a commercial heat exchanger without overheating? Over the next few days, I plan to answer that question.

For $1299, I sure hope so!

But seriously, it is one unique looking and interesting machine. I am looking forward to your review and results. I think this may be a machine that is looking for a market, so to speak. By that I mean, unless it ROCKS, no one is gonna shell out $1299 for a relatively unknown machine. Your review will answer the "does it ROCK?" question.

jesawdy wrote:By that I mean, unless it ROCKS, no one is gonna shell out $1299 for a relatively unknown machine. Your review will answer the "does it ROCK?" question.

No pressure there for my first review