|
|
|
 |
|
Contents |
| Introduction Espresso Performance Steaming Performance Materials and Workmanship Conclusion Appendix Videos |
Lever espresso machines are much simpler than their pump-driven equivalents. Subsequently owners expect that they'll offer years of trouble-free service, and if problems do arise, they'll often be addressable without a trip to the repair shop. With that in mind and my natural curiosity about how the Achille's pump and heat exchanger works, I disassembled the machine to nearly the last bolt. It took about an hour.
Once in pieces on the countertop, I noted Gaggia's attention to problems that plague older Pavonis. For example, the Achille's extensive use of stainless steel, such as the base and boiler. As mentioned in the introduction, the La Pavoni style lever machines have a screw under the drip tray, which potentially allows water to enter the base. This simply can't happen with the Achille.
In fact, nearly every part is chrome plated, or made of stainless steel and other corrosion resistant materials. The heat exchanger is stainless steel, the boiler, the screws, even the heating element appears to be made of stainless steel. The boiler covers are made of stainless steel. The support running from the bottom of the boiler along the length of the base is chrome plated. The group is chrome plated brass, the drip tray basin and handles are made of plastic and the water dispersion block is aluminum. Screws that are potentially exposed to moisture are copper dipped. The nuts that secure critical pieces like the boiler have nylon sleeves to keep them from working loose over the years. Corrosion and rust should not be a problem with this machine.
Under the base, the Achille uses a Mater pressurestat. The thermal breaker extends into the boiler and is attached to the heating element. If the boiler goes dry, the thermal breaker will trip, shutting down power to the machine. The breaker can be reset from outside of the machine via a small hole in the base. Simply insert a paperclip into the hole to reset (of course, after unplugging the machine!).
In addition to good component choices, the Achille has a very innovative system for pumping water through the group.
Forget how most piston-driven lever espresso machines operate. Clear your mind, this is not your normal lever espresso machine. In fact, it is more like a pump-driven heat exchanger espresso machine, but instead of an electric pump, you are using a hand water pump.
The key is in the double-action piston design. On the downstroke, the piston simultaneously draws water from the reservoir into the space above the piston and pushes water from beneath the piston through the heat exchanger and into the brew chamber. The water is flash heated and continues to the brew chamber beneath the pump. The diagram to the right shows the flow from start to finish (blue to red).
The piston is never in hot water. It is pumping from the cold side of the tank, just like an electric pump. Because the piston is isolated from the heat of the group, the seals will last longer than those that must endure frequent exposure to extremely hot boiler water. The piston is not exposed to coffee oils because the brew chamber is completely separate from the group piston. So there is never any need to remove the piston for cleaning. You just clean the dispersion block and shower screen just like any other pump operated machine.
Near instant boiler recovery. Predictable brew temperatures. Continuous steam. Fresh brew water, not boiler water. Seamless stainless steel base. No-burn boiler cover. No portafilter sneeze. Whew! That's a long list of smart design decisions.
 Contact Us |
Legal disclaimer and copyright: This content
and all its parts are copyrighted, all
rights reserved. Content including all text and images in part or in whole may not
be reproduced in any electronic or printed medium without prior
permission. Home-Barista, Home-Barista.com and related logos are trademarks of the site owner.
Other trademarks are the property of their respective owners. |
|
Have a question or just want to
talk espresso? Check out the forum and its