I'm interested in some more info about construction. Is the boiler/body solid aluminum? Is there actually a spring inside? Or purely hydraulic driven? Steam wand option? Sorry for ruining all the mystery and stealing the thunder!

I think as long as it can be demonstrated that it can meet loose regarded parameters for espresso extraction (~6-9 bar and 80-95 degrees), then it's clearly separated from the Moka pots that it closely resembles in a consumer's mind.

I assume you could set it up with a small electric hotplate? Could be a nice Caravel alternative for a small, espresso-only portable option.

Sounds intriguing!

We generally think that the Bacchi has been misunderstood from the beginning.....after all, it has been around for 5 years at least that we know of. The inventor/designer originally called it "La Carioca".

As you look at the machine imagine it as a single group, but upside down. If you were to turn it upside down and put a portafilter on it instead of the top part with the spouts it would be much clearer how the machine works. The physics of heat transfer to the brew water in the cylinder is quite well worked out. The spring that is visible is a bit deceiving since it is not the active force for extraction....the spring basically counters the initial pressure application from the force from below, which is supplied by the boiling water in the bottom sealed chamber. This counter spring provides a short but effective pressure profiling before extraction is at full pressure. The spring also serves to return the piston (located in the body of the machine, inside the cylinder) to the down position when setting up the machine for brewing.

Once the machine is assembled the bottom part is the boiler and power source (steam power) and inside that chamber are 3 pressure valves which vent into the body under the piston. One valve is set to release steam at a pressure just below ideal extraction (it serves as a small warning hiss) and the second valve is set to create a whistle sound at the extraction pressure and the third valve is an overpressure safety valve. When the extraction pressure is reached (and yes, this takes about 6 minutes when the heat source is set properly) the steam powered piston is activated by opening the valve above the filter basket and the piston is forced upwards by steam power pushing the heated extraction water through the coffee and voila!

The 54mm basket is rated to hold 15 grams and uses no tamper. The group, as it were, is self tamping and when set up properly there is no air space throughout the extraction column. After extraction the puck is compressed quite densely and upon disassembly only a small fraction of the water in the brew cylinder has been used in the brew process.

Steam wand...no. Hot plate, sure. The only requirement for the heat source is that is hot enough to get the time window right (which has as much to do with the proper brew temp of the water in the cylinder as anything) and that the heat is applied over the entire bottom surface...the rule of thumb is that the flame should be the same size as the outer diameter of base of the machine, so an electric element would serve just as well.

Hope this helps demystify it a bit.

Looks like it's for sale on your site now - $395? Definitely reasonable for a high quality, modern, niche machine.

Would be helpful to see a few more pics of the machine disassembled, how the portafilter is packed, etc. Is there any way to insert a thermometer of some sort, or are you reliant upon the various pressure whistles?

And am I understanding this right - the *steam* actually serves to compress the puck and squeeze out the espresso, not any physical pressing motion? Is this really enough to get some decent pressure?

Hi Louie....I'm working on design study for the machine to explain the function. Really very well worked out engineering ideas. We did a recent restoration of a 1948 Gaggia Gilda and the interesting thing about the old machine is the way that he, or they, worked out the engineering, manufacture, and design issues in relation to the available technology and market considerations etc. Same thing with the Bacchi....lots of problem solving and integration of functional design of the thing. Once you get a look inside most machines they are much more understandable.

Hi from Italy!
You can find more technical information on Wikipedia :
http://en.wikipedia.org/wiki/Pascal%27s_principle
http://en.wikipedia.org/wiki/Hydraulic_press

Lucio

Hi, this is my yesterday's double espresso.
I do love this machine!
coffee was not so fresh, however...

Well, I've bitten the bullet. One on the way over from Italy.......

Have had a chance to use the Bacchi for a few days now since it arrived carefully packaged and safe and sound from Orphan Espresso. A couple of observations - recognizing that I haven't had the machine long enough to even begin to explore its possibilities and these comments are initial and incomplete.

I have been pulling shots with the Bacchi using PTS Flying Monkey espresso blend. It is capable of making real espresso with crema - a rich satisfying shot. I'm poor on describing flavor but I have already had a couple of shots that were on a par with better shots that I have pulled from the other pump and lever machines that I use. As with all espresso machines there is a learning curve involved to get the best from it.

I have been surprised at how much fun the Bacchi is to use. The process of brewing is really simple. Add water in the bottom chamber to the fill line (about 1 oz). Fill with brewing water to the top. Grind 15 grams of coffee filling the basket to the top. Make sure the coffee is all inside the basket. No tamping at all. Assemble the machine. Firmly tighten the retaining screw on top. Place on the pre-heated burner. Wait 6 or so minutes until it whistles. Then turn the front knob slightly until coffee starts to flow after which the knob is opened about a quarter turn. I was very relaxed about using the machine after about the third use.

The two main parameters I have had to concentrate on have been grind and proper heating.

Getting the heating right takes brewing in a 6-7 minute window. Short of that or past that time the temperature does not appear to be right. Too cool if you get there too fast and too hot if it takes longer. I have a small, butane fueled gas burner that took about 7 and a half minutes to get the machine to brew temperature with poor results. Right now I am using the center element on a ceramic Kitchen Aid electric stove which brings it to brew temp in about 6 minutes and 15 seconds. I have ordered a butane stove with a broader and more intense flame that I hope will allow me to experiment more with brew times controlled by different heat.

I am experimenting with grind. Typically the shots have flowed too fast. I am going to need to adjust finer than I do for either the Termazona or the Speedster. I need to change the Vario so that it will grind a bit finer than it does now. The Versalab is grinding fine enough when I can hear the burrs touch a bit. I do not like to run it quite that tight. More work to do to get the right grind including trying a couple of hand grinders that are available. The puck is tightly packed after brewing - as though it had been firmly tamped. It is strange to do no tamping at all but it works.

The bottom chamber that creates the pressure in the machine develops a vacuum that "holds onto" the body of the machine after brewing. I have found that a light twist with a blade screwdriver is all that is necessary to break the vacuum to brew the next shot. You can make a shot immediately after the first by cooling the Bacchi with tap water (recommended in the instructions).

I have found that the Orphan Espresso video http://www.youtube.com/watch?v=YlLd0zSmlRg is a very helpful tic/tock through the brewing process.

My initial response to the Bacchi is very positive. I'm looking forward to more experimenting over the next several days.

Hal,

Thanks for your initial thoughts on the Bacchi. I was really curious about your comments on heating (too cold/too hot) and wondering if you thought the Bacchi could be used on a propane camp stove. I am looking for something that I can take with me camping. Do you think that this would work?

It sounds like you need a really fine grind. Simple Illy espresso (pre-ground) just isn't going to work is it?

Thanks again.