Clevis to Lever - further explorations in Espresso Space

A haven dedicated to manual espresso machine aficionados.
Dr Jim

Postby Dr Jim » Mar 01, 2006, 4:43 am

So it's been raining spring-lever machines here at the Lab - well, what would you expect in Seattle - it should snow Super-Automatics?

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This is a pretty remarkable commercial 58mm single group machine which has to be close to 30 years old. Imported by the 'Termozona' company of Hartford, Connecticut, it looks to use either a Victoria Arduino or Faema grouphead, has a 5-litre boiler, a massive Sirai pressurestat, and a couple of very heavy-duty soft-close steam valves - note the Marzocco-style pivoting steam wand which has a formed ball-end tensioned against its brass fitting by a spring.

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Another shot from the right side - the blessed machine looks like it was brand new inside - the boiler is shiny, there is no corrosion anywhere, and all of the pipes and fittings just gleam.

There are lots of nifty little engineering touches, the inside of the case is insulated with about an inch of pink fiberglass batting - not nasty asbestos - which appears to be remarkably effective and makes working on the machine much more pleasant than having to fight insulation glued to the boiler, there is an overflow line from the inlet valve to the drip tray, if the water supply burps the overflow is directed to the drip tray which has its own outlet tube.

What makes this machine unique, and very interesting to me, is that it uses a Heat Exchanger loop from the water input through the grouphead. My first reaction was "Weird, why would anyone want to use an HX loop on a Lever machine?" After all, the whole idea behind a massive lever group hung out in the air is for it to cool the too-hot boiler water down to an acceptable shot-making range.

Which idea works well, as long as the boiler and grouphead system are in thermodynamic equilibrium, but as any Pavoni Europiccola owner can easily demonstrate, after several consecutive shots it's pretty easy to exceed the capacity of the group to radiate off additional excess heat.

So how does a very clever designer deal with this problem - simple, they pass a small amount of the cool input water through an HX tube in the top of the boiler, and then route it to a water-jacket surrounding the group via a drilled passageway and several small ports above the piston which are exposed when the lever is lowered into its pre-infusion position.

The thinking behind this arrangement is so stupidly clever that it almost makes my brain hurt just following the logic, which I believe goes something like this:

"For the first shot so as not to 'shock' the group with cold water, the HX loop will be at the same temperature as the boiler to keep the group stable."

"For each suceeding shot, the HX water flow will become progressively colder since the HX loop's heat transfer rate is deliberately limited to match the grouphead's thermal transfer rate. Hence, the more shots you pull, the more the grouphead is cooled by the HX loop and thermal stability is acheived"

As a final piece of efficiency, the output of the HX loop isn't to the drain tray. No, as the lever raises the piston for the next shot, it also forces the HX water back along a passage in the grouphead mount into the boiler. Cute, not only is the group held temperature stable, as long as you're just pulling shots and not Americanos, the boiler remains very close to its original level, since the HX water neatly replaces the 2-3oz used per shot.

Using a Scace device mounted in a bottomless Astoria portafilter I was able to tune the machine to show consistent 203-204 degree F shot temperatures with the pressurestat set for 1.2 Bar, and acceptable flow rates. The shot temperature profile was essentially flat for the first 20-23 seconds and then rather rapidly declined to 198-199F after the lever had reached its stop.

This profile is consistent with what I've always been told about the big lever machines, that you need to pull the cup as soon as the lever bottoms out, letting any additional liquid spill into the drain tray - "The shot ends when the lever stops."

The spooky thing is that I was able to pull something like 15 consecutive shots about as quickly as I could manipulate the lever before there was any appreciable change in the water temperature - which went down to 195 F in a hurry as it became apparent I'd exceeded the capacity of the 110V - 1200 Watt boiler element to heat water.

I have no idea how many consecutive shots you could pull with a 220V element, but it would be an exhaustingly large number - far more than I and all of my few friends could drink ....

But enough propellor-head chatter, "How did it taste, Jim?"

In a word, "Fabulous - 17 gram ristrettos were rich, chewy, and utterly smooth - with no harsh, sour, or bitter notes, and cappuccinos made with 2oz pours and 4 oz of perfectly microfoamed milk where among the best I've ever had from any machine.

My thanks the Mr Perry, who brought his new baby to the Lab, along with the Scace device and an impressive Versalab grinder and patiently waited while I muttered and talked to myself.

He's had a few days to live with the beast now, perhaps he'll be so good as to post some follow-up impressions?

Cheers

Jim

BTW - information about this machine is very difficult to come by - I've seen an older two-group on Ebay, and a two-group of about the same vintage here in Seattle, but if any of the European members recognise this machine - we'd love to know more.
LMWDP #26

hperry

Postby hperry » Mar 01, 2006, 8:17 am

Termozona has an interesting history. Some 20 years ago she briefly debuted, for less than a month, in a local restaurant . The owners neglected to refill her and burned out her boiler element. The element was replaced, but pump-driven machines were gaining increasing currency and interest in levers flagged. From then to now she has patiently rested on the back shelf of one of Seattle's original coffee roasters, waiting to show what she could do. Her "big sister," a 2 group Termozona, has pulled sample shots for about the same period of time as the only espresso machine at that company. For all practical purposes she is a brand new machine.

Thanks to input from members of the Lever Group, and Dr. Jim's willingness to help me master the Cremina I have become increasingly fascinated with levers over the last four or five months. My experience with the Olympia was that on my best days I could fairly consistently pull better shots than I could on the Bezzera BZ40. But, largely within the narrow band of shots 2-5. It occurred to me that a commercial lever, with its ability to dissipate more heat might be an approach that made sense. I am aware that the barista is the key element in any machine delivering good coffee. However, my thought was that if the machine parameters were stable, and the grinder was good quality, then I could more readily sort out where I needed to improve my barista skills.

I'm very pleased with the results I'm getting so far, even though I'm just beginning to learn how to use her. Termonzona is very forgiving and the shot quality that Jim describes seems characteristic of her nature. I'm not much at "coffee language" but the shots are consistently sweet, rich, and full-bodied with the two coffees I have used (The Good Coffee Company espresso blend, and Caffe Fresco Ambrosia). She is a wonderful steamer if you use 6 oz of milk or more. You have to use care with less or you "cook" it. It produces very dense, smooth foam.

I am grateful to members of the lever group for getting me interested in levers. I am particularly grateful to Dr. Jim who took considerable time to help me with the purchasing decision and to understand the potential of the machine. His encyclopedic knowledge of all things coffee, and his generosity in sharing it, is a real gift.
Hal Perry

hperry

Postby hperry » Mar 02, 2006, 2:59 pm

I really like ristrettos that produce about .75 to 1 oz shots. Had developed a repeatable way of doing them with the Bezzera. Didn't work with Termozona. Turns out that its behavior is similar to the Olympia, just less fussy. Overfilling the double basket and doing my somewhat poor imitation of the Stockfleth move produced an incredible ristretto - the best I've done at home. The amazing thing to me is how much Termozona helps the process along without fussiness.
Hal Perry

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peacecup

Postby peacecup » Mar 02, 2006, 5:18 pm

I am grateful to members of the lever group for getting me interested in levers. I am particularly grateful to Dr. Jim who took considerable time to help me with the purchasing decision and to understand the potential of the machine. His encyclopedic knowledge of all things coffee, and his generosity in sharing it, is a real gift.


Here, here! Hats off to Steve Robinson and all of the lever "group" (no pun intended) for their help. They've certainly provided me with a lot a lever-age! I've also really enjoyed Dr. Jim's recent posts, and I'm looking forward to hearing about his next "new" lever machine.

I really like ristrettos that produce about .75 to 1 oz shots.


Dr. Jim and hperry- if you ever get the chance I'd like to hear about a comparison between a 1 oz. pull one of your commercial levers vs. one on Dr. Jim's Ponte Vecchio. I'd also like to hear how the PV compares to shots pulled on a Cremina. Since the PV is the only lever I've used I have no basis for comparison, and of course I'm looking down the road.

Cheers!
LMWDP #049
Hand-ground, hand-pulled: "hands down.."

hperry

Postby hperry » Mar 02, 2006, 8:15 pm

Dr. Jim would be the one to compare the Ponte Vecchio and is an expert in coffee language.

I am very poor with "coffee descriptions." But between Termozona and Cremina both will pull full flavored shots. The Cremina creates a nice crema, but tastes "thinner" than Termozona. Termozona produces a rich syrupy ristretto. Termozona allows you to manually speed up or slow down as does Cremina. However, the spring loading in Termozona works very capably in default mode. I am controlling the pulls largely by varying the tamp and grind so as to reduce the number of variables.

Clearly temperature stability, and the ability to hit a temperature set point is ridiculously easy with Termozona and more difficult to control with Cremina.
Hal Perry

Dr Jim

Postby Dr Jim » Mar 07, 2006, 3:48 am

Dr. Jim and hperry- if you ever get the chance I'd like to hear about a comparison between a 1 oz. pull one of your commercial levers vs. one on Dr. Jim's Ponte Vecchio. I'd also like to hear how the PV compares to shots pulled on a Cremina. Since the PV is the only lever I've used I have no basis for comparison, and of course I'm looking down the road.

Cheers!


Peacecup -

Unfortunately, my PV 'Lusso' is onboard our boat Nonchalant which I can't board until my new knee heals enough to negotiate steep boarding ladders, so I can only compare my (notoriously poor) memory of the PV to the Conti which is in daily use here at the Lab.

As I've raved about in other posts, the design of the Rivera-style group is such that the best extraction volumes range from 1oz 'singles' to 1.5oz 'doubles' - which, while they can be quite tasty, doesn't really satisfy my morning desire to have enough hot, mind-expanding beverage ready to hand that I can bear to contemplate each day's impending horror with some degree of equanimity - which these days takes a 2.5oz 'lungo' pulled from 20gm in a triple basket, capped with 3oz of micro-foamed milk in a Bodum 'Pavina' glass.

This drink is a snap to prepare on the Conti, whose 5 litres of water neatly foam the milk in the 10-15 seconds it takes to pre-infuse the triple basket, so the whole shot construction process is literally 'a minute's work.' On the PV, to make the same drink requires two full shots, a basket change, and some significant temperature management to get, and keep, the foam and the shots at their correct temperatures - all-in-all a much more laborious and painstaking ritual.

Also, I seem to get much greater volumes of denser and darker crema with the Conti than the Lusso, whose crema was always a relatively pale yellow-tan in color with visible 'bubbles' - I wonder if either the temperature of the PV is too low, or if its spring pressure is set too low? This is something I'll look at when I can get back to the machine.

Here's a hurried picture of a 2.5oz shot from the Conti:

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Note that this shot was taken roughly 20 seconds after the pour, during which the crema actually overflowed the glass, you can see how tall it initially was on the sidewalls.

Now, before you throw yourself off of a cliff in a major hissy-fit, please note that some small cheats happened here - the blend included Monsooned Malabar, Monsooned Indian Robusta, and Mexican Oaxaca coffees all of which contribute to excessive crema, and it was ground to perfection on Hperry's Versalab grinder, but I will admit it was a pretty exceptional drink.

Cheers

Jim
LMWDP #26

Dr Jim

Postby Dr Jim » Mar 07, 2006, 3:58 am

BTW - information about this machine is very difficult to come by - I've seen an older two-group on Ebay, and a two-group of about the same vintage here in Seattle, but if any of the European members recognise this machine - we'd love to know more.


In a frenzied fit of web-cruising, I managed to stumble on the site of a fellow who had restored one of these beasts here:

http://www.xs4all.nl/~hoffjes/DSC015124037b7464_jpg.html

So, it appears that the machine is a Brugnetti or Aurora 'Export' rebadged and sold under the Termozona name - which is consistent with what I saw, since I believe that Brugnetti is a smallish, semi-custom builder of very interesting and high-quality machines, although they are relatively unknown in the States.

My hat is off to the restorer, he was faced with a rather daunting job, since it looks like his example had been rather severely mistreated and abused - nice job!

Cheers

Jim
LMWDP #26

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srobinson

Postby srobinson » Mar 09, 2006, 12:57 am

Dr. Jim, many thanks for the writeup on this one. Glad to see some interesting posts on machines other than Pavonis, Elektras and Creminas. Now just to find and excuse to go to Seattle to get a pull or two on this baby.
Steve Robinson

LMWDP #001

hperry

Postby hperry » Mar 09, 2006, 10:49 am

Hi Steve,

Dr. Jim made first introduced me to his Conti, then made a huge contribution to my espresso-life by encouraging me to buy the Termozona and helping me understand its capabilities. It's great fun to just walk up to the machine and pull a shot with little fuss.

Plan to come to Seattle. I'd be honored to have you spend as much time with Termozona as you have available.

Hal Perry
Hal Perry

joecaffe

Postby joecaffe » Dec 05, 2006, 5:45 pm

It's nice to see people are still using our machines. We were the original manufacturer of the Termozona Old Italy machine. I speak of the brass two group unit. Saccuzzo Coffee Co. is the current name of the business. When we started out and during the manufacture of the Termozona, we were known as Mercantile Corp. The one group you have is well kept to say the least; we imported and rebadged it with a few tweaks for the American market. The two group units' parts were made for us by Tortorelli Meccanica in Siena per our specs and assembled here in Connecticut. Production ceased in 1985, though functioning units and parts still exist. We shifted our business from machines to the art of espresso roasting and for the past 20 years or so, we have been churning out true Italian espresso named Grande Italia. I only found this thread out of curiosity since we just got one in for repair.