This evening I decided to take a few measurements. I wanted to get the double basket capacity, physical dimensions and the amount of water dispensed with one pull.

I started with the basket volume, and was surprised at the consistency of the basket volume. While the Elektra uses a 49mm basket and the Gaggia Factory (La Pavoni pro 16) uses a 51mm basket the volume was very close. I used the same grind, overfilled the double basket and leveled off the basket with no down pressure. The Gaggia Factory weighed out at 12.8, 13.2, 13.2, 13.3 grams which averages out to 13.12 grams. The smaller diameter, but deeper, Elektra basket weighed out at 12.7, 13, 12.7, 13 grams. That averages out to 12.85 grams. So both machines double baskets are within 0.27 grams. I also checked the basket on the Gaggia Achille. The Achille uses a 58mm basket and weighed in at 15.5 gram dose.

I also wanted to check the volume of water dispensed with one lever pull. I adjusted both the Elektra and the Gaggia Factory to one bar of boiler pressure. I dosed the baskets as stated above. I used a 4 second preinfusion before I pulled, or released the lever. Both the Elektra and Gaggia Factory dispensed one ounce of espresso. I did not have the Achille hooked up so I did not measure it.

To finish things up, I got out the calipers to measure the baskets inner diameter and overall length of all three baskets. The Factory measured 51.6mm inner diameter and overall length (bottom of basket to top of lip) was 24.7mm. The Elektra basket had an ID of 49.57mm and an overall length of 25.4mm. Last was the Gaggia Achille which came in at 58.7 OD and overall length of 24.1mm. Both the Elektra and Factory baskets are straight sided, the Gaggia Achille uses a standard Faema style double basket which tapers in at the base.

So what did all of this measuring reveal? While the Elektra and Factory have different sized groups, the actual basket volume is very close and both machines dispense the same amount of espresso with a single pull of the lever.

HB wrote:... this weekend I pulled lots of Paradise Roasters' Espresso Havana:

Vibiemme Domobar Super:
Rich, thick crema with deep tobacco flavors. ...

Ponte Vecchio Lusso:
Surprising front brightness with tobacco finish...

... Paradise Roasters' describes Havana Espresso as "Deep and smokey - a heavy bodied espresso that can stand up to milk or a fine cigar"

With all that tobacco in the espresso itself, who needs the cigar!

HB wrote: Espresso Havana morphed under the influence of the spring-powered lever, becoming a brighter, fruitier blend with subdued tobacco notes. That is, a darker roasted coffee that I'd expect to have less varietal characteristics brewed more like its lighter roasted counterpart. ...

This jibes with my experience at the very low end of the brew pressure continuum, when pulling gentle (very easy on the lever) lungo S.O. shots on the Caravel. The lower the brew pressure, and the piu lungo the extraction, the more pronounced the varietal flavors become.... the cup loses in body but gains in expression of varietal flavors.

Regards
Timo

HB wrote:Narc comments above that "So far, the [Lusso and Microcasa] are pulling distinctly different types of espresso," but that wasn't my experience. It's trickier to compare them head-to-head because the Microcasa's brew temperature is a moving target.

I'm still pulling "distinctly different types of espresso" with these two machines. Pre-infusion (4sec), release lever, when 1st drops appear pull the lever gently down, release. Total volumes are similar. Total extraction times are similar. Grinder at set level. PVL tamped at ~#15, MCaL at ~#30. Significantly more headspace in the MCaL basket. PVL boiler pressure 0.95 to 1.05 bars, MCaL boiler pressure 1.0 to 1.2 bars. Will be dropping the MCaL boiler pressure down to 0.8-1.0 bars.

The espresso from the MCaL looks, feels in mouth & taste to me significantly different. Crema has more speckle & mottling, less in volume, less dense/creamy mouth feel than the PVL. My perception of the MCaL espresso taste is a brighter character with more distinction vs. the PVL espresso as more heavier, fuller but with less distinct character.

With all the variables I'm assuming that the differences in espresso is more due to operator than machine. That said, I'm beginning to feel that these machines do pull different types of espresso. How distinctly different is probably due to the person pulling the shots & a little luck. Life & espresso would be boring if it was a constant predictable replication of itself.

Any data available yet on the spring pressure gradient?

narc wrote:Total volumes are similar. Total extraction times are similar. Grinder at set level. PVL tamped at ~#15, MCaL at ~#30. Significantly more headspace in the MCaL basket. PVL boiler pressure 0.95 to 1.05 bars, MCaL boiler pressure 1.0 to 1.2 bars. Will be dropping the MCaL boiler pressure down to 0.8-1.0 bars.

You can get different shots from, say, the Cremina, merely by changing the shape of the single basket, with all other variables the same: dose, tamp, grind, roast. So, when you say you're tamping twice as hard on the MCal as you are on the Lusso and that their pstats are set differently, you are not really comparing apples to apples... not that you ever could when the machines have such radically different temperature-management designs. But pstat setting, tamping force (different here to compensate for some differences in the machine), basket shape/height-to-width-ratios, are hardly insignificant variables.

Regards
Timo

narc wrote:Any data available yet on the spring pressure gradient?

The pressure gradient is linear with volume on the Lusso. It takes 2 pulls to pour a shot of around 3/4 ounce, the way I 've been doing it. I'm not letting the first pull go to completion so that the cake doesn't get so riled up when I recock the lever. So the profile is a sawtooth with two teeth. Max pressure is around 100 psi or a little less. Min pressure is 50 or a little less.

-Greg

narc wrote:
The espresso from the MCaL looks, feels in mouth & taste to me significantly different. Crema has more speckle & mottling, less in volume, less dense/creamy mouth feel than the PVL. My perception of the MCaL espresso taste is a brighter character with more distinction vs. the PVL espresso as more heavier, fuller but with less distinct character.

I should prolly report what I've been up to the last day or so WRT 2-group Lusso testing. Fundamentally I really hate the fact that I have to use two pulls in order to produce a larger than microscopic shot. Since I'm pulling shots with a nekkid portafilter I can see how the second pull disrupts the coffee cake if I'm not careful. But I've gotten the hang of it, I'm getting reasonable reproducibility, and I'm quite fond of the shots I'm getting. As Narc posted, the shots are very creamy. I find them smooth, and generally sweet. On the other hand a lot of the flavors that are present in the Marzocco shots are diminished in the Lusso's more chocolatey, less distinctive flavor. That's good if the flavors are excessively bright or metallic. I think the Lusso is more tolerant of bright coffees than the Marzocco for sure.


The pressure values that I obtained over the last weekend weren't all that surprising considering how coarse of a grind I needed to use with the Lusso compared to the Marzocco. In order to get both machines more on the same page, I reprogrammed the marzocco's pump on Monday to produce a linearly declining pressure profile, with maximum pressure of 100 psi (measured with a scace 2) and minimum of 50 psi. The pre-infusion was 2 secs at about 30 psi, with a second order (concave up) pressure rise to max pressure taking place over 3 seconds. These values are substantially lower than the 135 psi to 90 psi that i was using, and the shape of the decline is different as well - straight line with increasing time, rather than curved. Shots brewed at these pressure were more similar to the Lusso's. They were somewhat sweeter, but the brighter notes were more muted. I don't have all of the puzzle pieces yet. I still haven't gotten temperature data, and the basket shape has to have some effect. I like the shots brewed from the marzocco at these relatively low pressures. For a while now I've thought that Illy and whoever's canonical 9 bar optimum pressure didn't really hold up to scrutiny because there's no supporting documentation on how the 9 bars gets measured. If measured under conditions of no liquid flow, such as when one uses a pressure gauge mounted to a blind filter basket, the real brewing pressure is over-predicted. The amount of over-prediction varies from around 3/4 bar to as much as 4 bars, depending on the machine layout and pump used. Pressure drop in pump-driven espresso machines is due to friction losses in tubing / plumbing, and restrictions that are created by group solenoids, group passages, gicleurs, etc. Since lever machines have much fewer impediments to fluid flow between the spring-actuated piston immediately above the coffee, as compared to a pump machine, I would expect that the Lusso's relatively modest brew pressures are within reason. Certainly my taste buds think so, and I'm trying to duplicate some of the Lusso's flavor profile in the Marzocco, rather than the other way around.

This AM, I reprogrammed the Marzocco's pump again, using the same maximum and minimum pressures, but changing the shape of the pressure declination. Today's profile has relatively higher pressure than the Lusso in the second third of the extraction, but relatively less pressure than the Lusso in the last third. I came away from this AM's caffeinated tongue thrashing with the sense that the non-linear pressure reduction added some flavor nuance, but I'm not entirely sure if it's better or not. I'll have to go back and forth a bit to see which I prefer.

My opinion of the Lusso right now is that one shouldn't get too hung up on the double pull thing. It's only a big deal if you absolutely have to have big shot volumes. If, on the other hand you're flexible and observant, you can get some pretty killer coffee for your 1100 bucks. The Lusso is very tolerant of coffee. Brightness and distinct flavors are diminished compared to my benchmark machinery. Whether or not that is your cup of coffee is up to you.

-Greg

gscace wrote:For a while now I've thought that Illy and whoever's canonical 9 bar optimum pressure didn't really hold up to scrutiny because there's no supporting documentation on how the 9 bars gets measured.

Right on brother!

Fundamentally I really hate the fact that I have to use two pulls in order to produce a larger than microscopic shot.

I did too for a while, but now I just go with the flow. I'm not using the naked PF, but its gotten much easier for me take two or more pulls without causing the puck to be disturbed (at least by looking at it afterwards).

If, on the other hand you're flexible and observant, you can get some pretty killer coffee for your 1100 bucks.

Right on brother (I might add that the Export, which shares the same group, can be had for ~$500).

PC

peacecup wrote:

gscace wrote:For a while now I've thought that Illy and whoever's canonical 9 bar optimum pressure didn't really hold up to scrutiny because there's no supporting documentation on how the 9 bars gets measured.

Right on brother!

Let's not dis the good Illy. In The Chemistry of Quality :

Volume: 25-30ml
Ground coffee portion: 6.5 ± 1.5g
Water temperature: 90 ± 5° C
Inlet water pressure: 9 ± 2 bar
Percolation time: 30 ± 5 seconds

gscace wrote: I really hate the fact that I have to use two pulls in order to produce a larger than microscopic shot.

Microscopic Hyperbole, from a scientist

Regards
Timo

timo888 wrote:Microscopic Hyperbole, from a scientist

Regards
Timo

+- 2. Aha! Sorry Mr. Illy. FWIW 7 bars is roughly 101.5 psi, which the Lusso barely reaches at full pressure.

-Greg

timo888 wrote:Inlet water pressure: 9 ± 2 bar

But it also says inlet pressure, where is the inlet? That could make a big difference. As you noted pressure drops as you snake your way through the inner workings so if the inlet measurement is just after the pump, the group pressure could be a bar or two lower at the puck.