One week with the La Marzocco GS3 - Page 3

[mogogear]

I'm sure you'll really appreciate the first one

You know it. Thanks for the shots.

[Jacob]

Sorry Marshall, I don't know this prototype GS3's capacities, heating element wattage, etc. BTW, it's not shown in the photo, but the pump is underneath the smaller boiler and it's easily seen from the front when the driptray is removed.

The brochure says 3.5 and 1.5 liters 110V-15A or 230V 8A - 8 amps

The brochure lists a couple of points where one says "Brew water pre-heating system".
Can anyone tell how this pre-heating takes place?

[AndyS]

Dan,

The GS3 spec sheet says each boiler is "5 liters." From your photo, I'd say that's impossible. Do you have the correct capacities?

In his review, malachi said: "3.5L PID controlled stainless steel steam boiler, 1.6L PID controlled stainless steel brew boiler."

[HB]

Today was a nearly effortless exceptional espresso day. Really, really good.

It began simply enough with how I've started the rest of this week, by confirming the GS3's setup with a few test shots of Toscano. They were roasted last Friday and some would claim they'd be showing their age, but damn it was good. Chocolates you would need an SUV to climb, smooth and rich. Next up was a coffee that I was anxious to revisit after Abe introduced it to us at EspressoFest 2006:

That Yirg blew me away as espresso. The first Yirg to really make it as an SO. The shots we pulled of Miguel's roast at espressofest were so delicious, I think I had five of them, and by the time I finished feeding the hungry crowd the bag was gone.

What really got me excited is how versatile that coffee can be. It is extremely sensitive to dosage temp & extraction volume, and I'm saying it as a compliment. By changing those parameters, one can produce a different cup in every shot. I ordered 5 lbs of it green from Paradise Roasters, and I'm going to start experimenting with it in different roast levels. It will make a perfect coffee for a workshop entitled Exploring The Extraction Space, and I am thinking of putting together such a workshop in New York. Miguel is really pushing the envelope with espresso, and I'm thankful for that. He promises some new and exciting SO's in June.

Miguel sent me this coffee last month to review. At a light roast it was to regular Yirgacheffe as honey is to flowers, yrg-honey, so to speak. Since my first taste, I was jonesing to try it as espresso. There must be something in the air, since at the SCAA it appeared in three different guises as espresso. Heather Perry, former US Barista champ, used it as the center piece of her blend in competition. Steve Schulman of Dallis Brothers casually produced a bag of it in a darker roast, labelled as an ultra-premium espresso. In Miguel debuted his SO roast at the espresso fest, where it completely wowed all the participants.

(cont'd)

I neglected to re-read the above comments this morning and wrongly assumed it would be fussy as an espresso. But like Abe said, when you zig, it zags in a pleasantly surprising way. Part of the pleasure of this coffee is its uniqueness. The fragrance is sweet and light, a floral, fruity scent reminiscent of peeled white grapes. Remember to take in this wonderful smell as the grinds fall into the doser. In the cup, its gentle roast notes tame the acidity and offer an intriguing counter-balance to the more whimsical floral-lemon sweetness.

(Meta-comment: In my search for a better description of the fragrance, I asked a non-coffee drinker friend to smell the beans and even provided some suggestive hints. "Smells like coffee" was all I got. Bah!)

Another friend of mine is really into cars, more than I'm into espresso (seriously). He likes espresso too, but he had to ask how to spell "barista" to find this website. The past few weeks he's been asking me about super-autos. Richard has patiently listened several times why he should reconsider, but I haven't changed his mind, even after he was served disastrously bad espressos at Williams-Sonoma. The lure of the reputably "baddest home espresso machine on the planet" proved too tempting for the hardware junkie in him, so he stopped by to check the GS3 out. I wanted to challenge him with something off his regular menu, so I served him Yemen. "Woah, that is really something different!" were his first words. Heh heh... he asked me about borrowing an E61 and grinder next week while he's on vacation. Another espresso lover saved from decades of mediocrity? Here's hoping.

Bill Crossland describes the GS3 as an "easy" machine. I believe he says that it may or may not make better espresso, but it definitely makes it easier.

I know where he's coming from with that observation. I spent a few hours demonstrating the finer points of HX temperature management using an E61 thermocouple adapter:


With the chorus of praise for the GS3, some not-gonna-be owners may feel less enthralled with their own gear. Bill's comment may offer them some consolation, i.e., you may have to work harder for the same result, but your current setup isn't necessarily incapable of [*] the same result.

(*) I originally wrote "nearly the same result," but the week's not over...

[malachi]

The heat thing sounds a little scary. So will we have an article pretty quickly after the GS3 reaches market called "How to Insulate the Boiler of your GS3?"

That would be a bad idea.
It would be very likely to result in degraded temp stability for the machine.

[malachi]

I'd hoped that a production model would have less of a discrepancy between gauge readout and actual temp - it better for the price!

Why?

If the brew temp is accurate to the temp that you program - why does it matter what the display says when you're not programming it?

[HB]

Yesterday's extreme HX temperature tuning exercise was put to good use today. Jim asked me to run a quick side-by-side of an E61 and the GS3. Nothing statistically significant, just an off-the-cuff answer to the question: Can the GS3 make his house blend a whole lot better than my E61 espresso machine? His house blend:

My blend is a pretty basic Ethiopian, Brazil, and Indo combination. 37.5% Yellow Bourbon, 22.5% Ghimbi, 15% Harar, 10% Yrg, and 15% Aged Sumatra. The over-complicated mix of Ethiopians is simply because I have lots in stock, and I remix it to keep the taste roughly right as the beans age or new lots come in...

I pull the blend at the iconic 202F - 204F, about 1.25 ounces to a well packed Faema style basket.

First, my gut reaction: When the E61 was at its absolute best, the espressos were very, very close in terms of flavor profile and tactile balance. I used the same grinder and they poured nearly the same visually. The GS3 poured a little more slowly (enough to suggest a 0.5mm grinder adjustment). Instead of running two grinders, I tweaked the amount of grounds by 0.75 grams. That got it within a couple seconds of the same extraction rate and volume.

I liked the blend as a ristretto, almost as much as Abe's homeroast he nicknamed "The Big Lebowski" (sorry Jim, it was more "interesting" in the finish; he never told me the composition). Back to Jim's homeroast, I was surprised how much it changed as a double versus ristretto. Many blends pick up bitters / harshness as they tighten to 1.25 ounces, but his held nicely and added sweetness that was lost at the higher volume, where it increased in brightness.

Keep in mind that I only sampled three pairs. I am almost convinced the shots coming from the GS3 had more generous mouthfeel and better clarity (i.e., you taste different individual flavors as the shot lingers in your mouth). However, with such a small sample and knowing which machine produced which shot, I could be projecting my own reaction. To my own defense, I noticed shadows of the same thing in an (unpublished) E61 versus Elektra A3 comparison, so it may not be utter hogwash.

Of course, these results are not easily produced on the E61. The "humpness" of E61 espresso machines can be twiddled to emulate an GS3-like flat profile and with nearly the same precision, but it requires warm up flushes and very careful attention to timing. Not all HX machines have this sort of malleability. For example, the Cimbali Junior's initial temperature spike was immutable (even Ken Fox's PID'd version retains this characteristic), and the A3's temperature hump was modest and immutable.

To its credit, the GS3 would be able to reproduce these results with ease for one person or a crowd. Semi-commercial E61 espresso machines like mine require you to stand on one foot, swing a bloody chicken, and count to twenty on your fingers and toes to produce the same result. In the end, that's a lot of what you're paying for - ease of use and reproducibility. It's a big premium. It goes without saying for many HB members, but for the newcomers, I would remind them them that the coffee, grinder and technique are well ahead of the espresso machine in importance - even one as forgiving as the GS3.

[another_jim]

In fairness to the GS3, this test is "cooked" towards the E61. This is my house blend, developed to be used on my set-up. i.e. the Tea. Dan's Valentina has the solenoid group rather than the levetta, but the same boiler and HX. In a side by side several years ago, the machines were indistinguishable. So the blend should "fit" his machine to a tee.

[Teme]

LM has an insulation wrap for the machine and have been experimenting with variations on it. So insulation may or may not make it onto production versions.

The prototype I saw at the factory a couple of weeks ago had insulation on both boilers (plus a paddle group).

The brochure lists a couple of points where one says "Brew water pre-heating system". Can anyone tell how this pre-heating takes place?

There's a heat-exchanger through the steam boiler.

Br,
Teme

[AndyS]

There's a heat-exchanger through the steam boiler.

And in addition, there's a hot/cold water mixing device. This ensures that any overheated water from the heat exchanger is cooled down before it enters the brew boiler.

[Dogshot]

Dan, I get the sense that you have taken a stance as an HX-advocate in these days of the DB craze. The following quote from your excellent review of the Vetrano is an example of what I mean by your attempt to balance the viewpoints on the 2 machine types:

"Much of what you'll read will focus on the extra steps heat exchangers require, a ritual known as the "cooling flush." Although dual boiler espresso machines simplify this necessity by dedicating a boiler to maintaining brew temperature, heat exchange machines are not without their own advantages such as:

* Reduced purchase cost
* Less parts means potentially reduced maintenance costs
* Consumes less energy
* Brew water is flash heated, so it's guaranteed to be fresh
* With practice, the barista can make minute temperature adjustments on the fly.

I demonstrated the last point one weekend when Steve Robinson, the Lever Espresso Machines forum moderator, stopped by to check out the Vetrano. He sampled an espresso made from Intelligentsia Kid O's Organic espresso blend. Although he thought the texture was excellent, he noted a sour finish and asked for a retry. Lately I had been toying with borderline low temperatures to favor the "gentler" flavors than are muted by higher temperatures, but who am I to argue? One of the advantages of a heat exchanger machine is that you can tweak the temperatures in small increments by flushing a extra couple seconds (however not with the level of precision reported for the La Marzocco GS3; the last degrees of temperature management on a heat exchanger rely on the barista's skill and intuition)."

In your opinion and given this perspective, does the GS3 offer the home-barista much more than the other DB machines like the Brewtus or the S1, and if so, in what ways does the GS3 make things easier/more consistent/better than these machines?

Thanks,

Mark

[Ken Fox]

Yesterday's extreme HX temperature tuning exercise was put to good use today. Jim asked me to run a quick side-by-side of an E61 and the GS3. Nothing statistically significant, just an off-the-cuff answer to the question: Can the GS3 make his house blend a whole lot better than my E61 espresso machine? His house blend:


First, my gut reaction: When the E61 was at its absolute best, the espressos were very, very close in terms of flavor profile and tactile balance. I used the same grinder and they poured nearly the same visually. The GS3 poured a little more slowly (enough to suggest a 0.5mm grinder adjustment). Instead of running two grinders, I tweaked the amount of grounds by 0.75 grams. That got it within a couple seconds of the same extraction rate and volume.

I liked the blend as a ristretto, almost as much as Abe's homeroast he nicknamed "The Big Lebowski" (sorry Jim, it was more "interesting" in the finish; he never told me the composition). Back to Jim's homeroast, I was surprised how much it changed as a double versus ristretto. Many blends pick up bitters / harshness as they tighten to 1.25 ounces, but his held nicely and added sweetness that was lost at the higher volume, where it increased in brightness.

Keep in mind that I only sampled three pairs. I am almost convinced the shots coming from the GS3 had more generous mouthfeel and better clarity (i.e., you taste different individual flavors as the shot lingers in your mouth). However, with such a small sample and knowing which machine produced which shot, I could be projecting my own reaction. To my own defense, I noticed shadows of the same thing in an (unpublished) E61 versus Elektra A3 comparison, so it may not be utter hogwash.

Of course, these results are not easily produced on the E61. The "humpness" of E61 espresso machines can be twiddled to emulate an GS3-like flat profile and with nearly the same precision, but it requires warm up flushes and very careful attention to timing. Not all HX machines have this sort of malleability. For example, the Cimbali Junior's initial temperature spike was immutable (even Ken Fox's PID'd version retains this characteristic), and the A3's temperature hump was modest and immutable.

To its credit, the GS3 would be able to reproduce these results with ease for one person or a crowd. Semi-commercial E61 espresso machines like mine require you to stand on one foot, swing a bloody chicken, and count to twenty on your fingers and toes to produce the same result. In the end, that's a lot of what you're paying for - ease of use and reproducibility. It's a big premium. It goes without saying for many HB members, but for the newcomers, I would remind them them that the coffee, grinder and technique are well ahead of the espresso machine in importance - even one as forgiving as the GS3.

You raise some interesting points, Monsieur Kehn, some stuff I've been thinking about the last week and especially the last couple of days during which I've been wasting a lot of time re-doing shot temperature profiles on both of my machines, now that I have an Omega datalogger that doesn't require me to type in every value that is going to show up on a graph. There are *real* differences in the shot profiles of my two machines, an almost-11-year-old Semi-Automatic Cimbali Junior "S" Vibe Pourover and a current version (3 years old) "D" version Rotary machine. One difference, that was "corrected" by replacing the old water output HX siphon in the older machine was that the machine would not reflect the fact that the boiler was heating up during the last half of the shot, so the temperature profile was constantly declining. That is no longer the case. BUT, there remains much more of the classical "Heat Exchanger Hump" in the profiles from the older machine than in the new.

These curves will illustrate what I'm talking about:

On the old Vibe Pourover, first the consecutive shot series and then the "Walk-Up" Shot series:

On the nearly new Rotary D Machine, consecutive shot series first then the Walk-Up Shots:

I do have other series at other temperatures where both the walk-ups and the consecutive shot series on the rotary machine both have obvious HX Humps, but many do not; I've not seen this on the old Vibe machine, period; it always has the hump.

And no, I have no idea what any of this means.

I think there needs to be some blind taste testing done on different machine temperature profiles before we get too convinced that there is anything magical about absolutely flat temperature profiles. In blind taste testing I've participated in on these two machines, with Jim Schulman, I've had a fairly consistent preference for the shots that come out of the older machine, and this was when the hump was more pronounced before I replaced the output siphon. Could it be the more consistent and pronounced "heat exchanger hump?" I don't know but it sure is possible.

Another point to make, in passing, is that the HX Humps in my machines are not necessarily "immutable." I set out to come up with some simple procedures (minimal and consistent flushing on both machines of the same quantity of water regardless of idle time and regardless of boiler temperature) that would yield a fair degree of walk up temperature stability. It might well be that with higher boiler temps and larger flushes one could duplicate the consistency I've shown, while eliminating the hump, if that was a desirable thing to do in the first place of which I am a doubter.

Finally, I leave you with this: if we accept that a temperature profile with a hump at the start that then declines, *might* produce a shot as good or maybe better than a machine with a flat profile, then how do we compare shots that look like this to a machine with a really flat temperature profile:

Once again, I have no idea what we would call this series, that starts out above 205F and ends up around 203F. How do we compare it to shots that have a truly flat temperature distribution? How do we account for the hump in assigning a temperature to this series to what might be a flat series at, say, 203.5F? The hump may be the one thing the HX machines have that is better than what you can get on a double boiler, so eliminating it in an attempt to make HX machines like dual boilers, for testing, would likely give the result that there wasn't a whole lot of difference in taste between the two types of machines, but that the HX machines were a PITA to deal with (to make them behave like double boilers).

ken

[another_jim]

The huge HX on the Junior will resist extreme changes in the profile. Nevertheless, Ken, you've certainly flattened out the profile by lowering your boiler temperature; and it's likely one could do a taste test with one machine set at around 1 bar with a long flush, and the other at 0.4 bar with a short flush, and compare relatively flat and humped profiles.

On the small HX/thermosyphon machines playing with profiles is relatively easier. A long flush shots down the thermosyphon, so the head cools and the HX water overheats rapidly. Therefore, waiting 30 seconds after a flush will produce a much more markedly humped profile, while overflushing, then doing an immediate shot will produce a flat or even rising profile.

I've toyed with the idea of insanely instrumenting my Tea with a sensor in the head, not at the screw, but in the part flooded by the thermosyphon, another sensor in the HX, and a control valve on the thermosyphon itself. This would allow one to produce machine states that reliably produced a given profile. Since I don't trust my plumbing skills, and since these custom-profile states would be good for one shot only, and then back to waiting for the machine to recover, I've resisted the temptation so far.

Basically, if a machine had the capacity to put a heavy brew head at one temperature, and the water supply at another, one could produce arbitrarily (one peak only) curved profiles. An E61 box roughly approximates this spec.

[annp]

That would be a bad idea.
It would be very likely to result in degraded temp stability for the machine.

Hmm, I'd think otherwise - but I'm approaching this from the perspective of insulating a water heater.

Ann

[another_jim]

Hmm, I'd think otherwise - but I'm approaching this from the perspective of insulating a water heater.

Ann

If you insulate the boilers after the PID is programmed, the cool off of the boilers when the heat is reduced will be slower, and the factory set P parameter will have too much gain (it shouldn't affect the I and D, since these depend on the speed of the feedback loop, not the process itself). Moreover, since the cool down is slowed, any temperature overshoot, now more likely, since the controller gain is too high, will take longer to fix.

It shouldn't be a problem if you can retune the controllers after insulating; but otherwise, there could be degraded control.

[annp]

Why?

If the brew temp is accurate to the temp that you program - why does it matter what the display says when you're not programming it?

My comment was in response to what Dan said:

"A few minutes with the thermofilter confirmed a three degree offset between brewhead temperature and displayed temperature"

Please correct me if I misunderstood your question or put Dan's comment in the incorrect context.

How would you know how to program it without establishing parameters manually?


Ann

[annp]

If you insulate the boilers after the PID is programmed, the cool off of the boilers when the heat is reduced will be slower, and the factory set P parameter will have too much gain (it shouldn't affect the I and D, since these depend on the speed of the feedback loop, not the process itself). Moreover, since the cool down is slowed, any temperature overshoot, now more likely, since the controller gain is too high, will take longer to fix.

It shouldn't be a problem if you can retune the controllers after insulating; but otherwise, there could be degraded control.

Now that makes sense!

Thanks Jim!

Ann

[RapidCoffee]

Re insulating the GS3 boilers:

That would be a bad idea.
It would be very likely to result in degraded temp stability for the machine.

In that case, why wasn't this state-of-the-art machine designed for optimal thermal stability with insulated boilers?

Mini-rant: Why is boiler insulation the exception rather than the rule on espresso machines? The small added expense of insulation seems well worth it over the machine lifetime.
__________
John

[Nick]

One of the unique elements of the GS3 is that thermal stability is achieved by smallness, not by largeness. Much in the way that a 100-hp small and great-handling car can be much faster than a larger, heavier musclecar on a racecourse with a lot of curves. PID allows for the foundation of this "smaller is more stable" technology.

Insulating the boilers would basically handcuff the system, robbing it of the "cooldown" attribute that the smallness affords. Heating up an espresso machine boiler is easy. Cooling it down is (traditionally) harder. It's much easier with a small boiler.

[RapidCoffee]

One of the unique elements of the GS3 is that thermal stability is achieved by smallness, not by largeness. Much in the way that a 100-hp small and great-handling car can be much faster than a larger, heavier musclecar on a racecourse with a lot of curves.

Agreed. (I drive a WRX. )

Insulating the boilers would basically handcuff the system, robbing it of the "cooldown" attribute that the smallness affords. Heating up an espresso machine boiler is easy. Cooling it down is (traditionally) harder. It's much easier with a small boiler.

I'm no espresso machine design engineer. But (off the cuff response): couldn't you quickly and easily reduce the boiler temperature by introducing cool water?
________
John