I will chime in on this one. Since I recently hacked my Isomac Millennium and added an onboard pressure gauge, I can watch the pump pressure as the element cycles on. There is most defiantly a difference in pressure. The pump gently builds pressure to 9 bar during the pre-infusion, about 6 seconds from 0 to 9 bar (guessing here, I did not time it but that should be within a second). It happily sits at 9 bar for about the first 18 seconds of the extraction, then the boiler element kicks on. The pressure abruptly drops to about 8.5 bar for 4 seconds while the boiler heats, then jumps right back to 9bar for the remaining 7 seconds.
If you can hold that boiler temp throughout the entire extraction you get a cleaner cup. If I play with the temp, I can almost get an entire extraction without the element kicking on. Just one more reason to either upgrade to a larger boiler or use better insulation on the boiler (I used foil backed pipe insulation, not very efficient but it still made a difference).
That is one of the primary reasons I want to upgrade to a ‘pro’ class machine, and one reason I don’t often drink straight shots at home. Even with my modest barista skills, I will never be able to produce the sublime, smooth cup that a commercial machine can crank out. My shot are good, very good IMHO, better than anything I have had in any Ohio café. The equipment just cant keep up.
cannonfodder Senior Member Joined: 14 Dec 2004 Posts: 864 Location: Dayton, Oh Expertise: I live coffee
Espresso: ElektraA3,Faema2G, Isomac,... Grinder: Cimbali, Mazzer Vac Pot: Dont smoke pot or vac it. Drip: Press pot Roaster: Hottop, drum roaster
Posted Sun Nov 13, 2005, 7:49am Subject: Re: Introducing the La Marzocco GS3
Another thought, this could also be why a good barista can pull a better shot on a lever machine than you can get out of a prosumer vibe pump, 110 volt under powered home system. There is no drop in the brew pressure. With the lever you get a steady fluid application of pressure.
To further qualify your comment, the lever action may be smoother, but the pressure dropoff for levers like the Elektra Microcasa a Leva is steep as the spring decompresses. Some lever espresso machine aficionados strongly prefer the fully manual machines for this reason, i.e., they can "finesse" the brew pressure during the extraction.
AndyS Senior Member Joined: 10 May 2003 Posts: 474 Location: NY
Espresso: Tricked-out Silvia Grinder: Robur, M3, Mazzer Mini Vac Pot: Yama Drip: no, I don't have a Clover... Roaster: PIDed Popper
Posted Sun Nov 13, 2005, 8:54am Subject: Re: Introducing the La Marzocco GS3
dan_kehn Said:
To further qualify your comment, the lever action may be smoother, but the pressure dropoff for levers like the Elektra Microcasa a Leva is steep as the spring decompresses.
I'm not sure if this has been discussed, but recent spring pressure measurements have disclosed that some lever machines make good espresso at pressures that are very low by pump machine standards (6 bar and under).
Given these observations, doesn't it seem that the speculation about "flutter and wow" shortcomings in pump pressure waveforms may be unnecessarily putting a microscope on the situation, while overlooking the fact that the gross pressure measurements between pump and lever are wildly disparate?
AndyS Senior Member Joined: 10 May 2003 Posts: 474 Location: NY
Espresso: Tricked-out Silvia Grinder: Robur, M3, Mazzer Mini Vac Pot: Yama Drip: no, I don't have a Clover... Roaster: PIDed Popper
Posted Sun Nov 13, 2005, 8:57am Subject: Re: Introducing the La Marzocco GS3
cannonfodder Said:
That is one of the primary reasons I want to upgrade to a ‘pro’ class machine, and one reason I don’t often drink straight shots at home. Even with my modest barista skills, I will never be able to produce the sublime, smooth cup that a commercial machine can crank out. My shot are good, very good IMHO, better than anything I have had in any Ohio café. The equipment just cant keep up.
It's fun to "lead with the wallet," investing in increasingly expensive espresso equipment. However, I believe most consumers with a few thousand dollars burning a hole in their pockets would be wiser to invest in training than upgrades. The barista training at Intelligentsia is a reasonably priced introduction ($175 for half-day) and David Schomer offers an intensive training course ($1000 for three days).
These days I find myself dreaming less about the latest hot espresso machine and more about learning from the very best of the industry. What, the end of upgrade fever!?! Did I just say that?
Posted Sun Nov 13, 2005, 9:32am Subject: Re: Introducing the La Marzocco GS3
AndyS Said:
Given these observations, doesn't it seem that the speculation about "flutter and wow" shortcomings in pump pressure waveforms may be unnecessarily putting a microscope on the situation, while overlooking the fact that the gross pressure measurements between pump and lever are wildly disparate?
I fully agree. Furthermore, I assert that armchair engineers feel compelled to correlate physical measurements (temperature, pressure, or whatever is the metric du jour) and the in-cup results. I'm guility of this myself and have accepted it as folly. It was a humbling and liberating experience.
cannonfodder Senior Member Joined: 14 Dec 2004 Posts: 864 Location: Dayton, Oh Expertise: I live coffee
Espresso: ElektraA3,Faema2G, Isomac,... Grinder: Cimbali, Mazzer Vac Pot: Dont smoke pot or vac it. Drip: Press pot Roaster: Hottop, drum roaster
Posted Sun Nov 13, 2005, 9:42am Subject: Re: Introducing the La Marzocco GS3
You will get no argument from me. As I said, I have modest barista skills. I do have to rebuttal with one observation. Once you reach a point, your skill set no longer becomes as drastic of a factor. When you can repeatedly produce the same quality (or very close to the same quality) in the cup from shot to shot, the equipment does begin to play a part. Have my skills reached that point? That is up for debate. Some days I would say yes, others, no. However, you are always left wondering, what would it be like if I had ????
But to Marks comment, with my machine, there is most defiantly a drop in pressure when both the heating element and pump are engaged. When I can minimize that cycle, or even eliminate it, I do notice a difference in the cup.
In regard to the lever machine, I have not had the opportunity to sample a shot from a spring assist machine. My Gaggia Factory is manual, pure arm power, so that is what my initial observation was based on.
I occasionally have to remind myself that no matter what I have, there will always be something bigger and better on the horizon. Machines often remind me of technology, if you purchase it today it will be state of the art, but next week it will be outdated.
AndyS Senior Member Joined: 10 May 2003 Posts: 474 Location: NY
Espresso: Tricked-out Silvia Grinder: Robur, M3, Mazzer Mini Vac Pot: Yama Drip: no, I don't have a Clover... Roaster: PIDed Popper
Posted Sun Nov 13, 2005, 9:50am Subject: Re: Introducing the La Marzocco GS3
dan_kehn Said:
I assert that armchair engineers feel compelled to correlate physical measurements (temperature, pressure, or whatever is the metric du jour) and the in-cup results. I'm guility of this myself and have accepted it as folly.
As a "card-carrying" armchair engineer, I'm puzzled by your statement. Correlating physical measurements and in-cup results is folly?
Physical measurement are irrelevant? I guess you're saying that a professional barista should be able to make excellent espresso with a pot of boiling water and a sock. Please explain.
I wasn't referring to you or to anyone in particular.
My point is that it's tempting to take a few measurements and draw broad conclusions. For example, "machine X has measurably better intra-shot temperature stability than machine Y and machine X produces better espresso" and conclude that is the causal factor. Could be, but also could be a dozen other differences between machine X and Y. Few home enthusiasts have the means to manipulate a single variable for side-by-side comparisons. Mark mentioned the superiority of rotary over vibration pumps. I don't have two identical, perfectly calibrated machines on my countertop with only that difference, so I hesitate to cite it as a causal factor, despite my intuition that his assertion is indeed correct.
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