First post for a long time lurker.

I've been reading a lot about the mypressi twist and other similar machines and it got me to thinking if there has been attempts to make a home/bench machine of a more traditional format that use air pressure as the motivation for extracting the espresso. it seems to me that it would allow a number of benefits from a lever machine- easy pressure ramping, taper at end of shot and such. Just a crazy idea and was wondering if there has been any attempts at such a machine. Just to be clear, i'm talking about a using compressed air to drive water out of a thermostat controlled boiler. such a machine would sound really cool in operation at least. Ideas??

Peter Giuliano from Counter Culture was in town last week and we discussed this very subject! And not just for espresso machines, but why not an air-powered grinder? OK, they probably would not generate enough torque, but still, air-powered tools are much smaller and less expensive than those driven by electric motors.

Abe reported on a prototype pneumatic espresso machine in 2005: The Air Pump Driven Espresso Machine. I believe it was demonstrated at an SCAA conference using a converted Reneka Techno; I don't recall hearing anything beyond the buzz is generated after the show. Maybe the newfound interest driven by the mypressi TWIST will reawaken the design (?).

Hi guys,

but still, air-powered tools are much smaller and less expensive than those driven by electric motors.

Sure but what about the (usually) huge compressor with a very noisy motor on top of it? Yes you can get a small compressor (say from a fridge), but the smaller the tank the less stable the pressure and more frequent pressure build ups.

Regards,
dsc.

Lino Verna was busy on one afaik. Can't find the thread.

An air powered grinder? Do the amish drink coffee? They've got lots of air-powered tools.

dsc wrote:Sure but what about the (usually) huge compressor with a very noisy motor on top of it?

Peter and I talked about compressed gas cylinders, i.e., the mypressi TWIST NO2 cartridges on steroids:


From Gas cylinder (wikipedia)

Compressed inert gas (nitrogen or similar) would likely be a better option than air. It's a great deal less soluble in water. Carbonated espresso anyone???... Interesting post from back in 2005- Wonder where they went off to?

Thinking one could conceivably design a system so that the ramp off was adjustable by utilizing a variable volume pressure tank. You could also do preinfusion by directly injecting the boiler. It's all very interesting. I might be doing violence to my Aroma machine on the work bench here once it's shiny new replacement comes.

Hmm, if you're worried about gas dissolving in 200F water, you can always piston-couple the pressure delivery... It's Schectermatic Schecterator time!


Did Andy ever describe this beast [at length] on HB? I can't find it.

Man, what a woman, she could pressure profile an espresso with the power off.


-C

I am no engineer. The question arises in my mind: if you are pushing a piston, why not use liquid like in hydraulics and control the water temperature separate from the piston system?