Do any levers have heat control?

[Alchemist]

I am the proud owner of a Gaggia Factory and am rather happy with it. I know it is very similar to the la Pavoni's, but I can't say I notice any particular overheating that is often the case with those. I know that water has to be over 212F, I just likewise note that my shots are not burned. I don't pull a lot back to back, so it may be as simple as that.

That rambling aside, do any lever machines have heat control and/or don't over heat after a few shots? I have looked around and it seems even the much sought after Cremina has no mechanism not to over heat. It is a boiler supplying overheated "non controlled" water.

I know the new Achilles might have some group cooling plumbing, but I have not seen anything definitive yet.

[Hogfire]

Hello Alchemist,

Fellow Factory worker here! What size is your machine and how are you getting along with it? I've had mine for a year now, and I'm still learning more of its "secrets and quirks", and I love it. With beans that I roast myself, I'm able to achieve a cup full of crema and flavour that I never achieved with a pump machine. Mind you, I've owned both a Silvia and an Expobar Office Lever, but I didn't dedicate myself to them and learning as much as I have with the Factory. The only temperature control I'm aware of on the machine itself is an adjustable pressure stat located in the base. If you decide to adjust it, please read up on the matter first, as some machines have their adjustable ring glued into position, and some users have actually broken this ring trying to force it to move. The pressure stat on mine was not glued, and I set the pressure to .5 -.6 on the gauge. This is about as low as you can go so that water will still enter the grouphead, but it provides the best temperature/taste with the beans I've used. This also weakens the steam pressure, but I haven't really noticed it to be detrimental.

AFAIK, almost every home lever machine will overheat at the grouphead if used to make more than 3-4 doubles, just a matter of physics. The Olympias and Elektras have more mass at the grouphead, resulting in better radiating of excess heat, but they will still overheat. Home lever machines are for intimate espresso making only, not for entertaining say more than 3-4 people at once. I've heard that commercial lever machines can pull hundreds of shots in a day and not overheat, due to their massive groupheads providing temperature stability. Here is a review of the Factory by a Canadian coffee site where they claim to be able to pull after shot without burning the espresso (last paragraph). I don't buy it, but then again I've never tried to make more than 4 successive doubles myself.

http://www.coffeecrew.com/content/view/33/27/

At any rate, I only use this machine for myself, and sometimes someone special during a visit. It's absolutely perfect for such situations. I reckon this machine would be a nightmare if you attempted to use it to entertain a house full of guests.

I've taken a quick look at your site, UHMMMMM chocolate good! I also plan on shifting to Portland after I finish my masters here in the mid-west. I miss the natural beauty and progressive mind-set of the PNW. Try to keep housing prices low until I arrive, would ya !

Hogfire

[hbuchtel]

That rambling aside, do any lever machines have heat control and/or don't over heat after a few shots?

The Presso! Heh heh. Stretching the definition of 'control' perhaps, but it's very unlikely to overheat!

Henry

[cannonfodder]

Or make one yourself...

[Alchemist]

That is just what I want to do I think. I think I will use your path and add to it. I recall seeing it still had a band of ±1 F IIRC. I can live with that but thought I would add a second lead (or another TC) to show me what the boiler temp is right then, so I will have a target temp and actual temp and wait/surf according.

I am now mulling over how best to add a lever hand pump to give head pressure so that I can keep the temperature sub boiling but still have pressure to deliver water to my group.

Little by little.

Oh, but it does sound like there are not really any home levers with temperature control. Just the nature of the beast I guess.

[cannonfodder]

Don't get too excited about it. My results were a bit mixed. While it does let me control the temp of the boiler, the design of these machines requires more heat to pressurize the boiler than is optimal for brew temp. After a lot of playing, the sweet spot on my machine is 233F. That gets me just enough pressure to do the job. Out of the box, it runs around 243F.

My final thoughts...

http://dirty-portafilter.blogspot.com/2005/12/caveat-to-lever-machine-temperature.html

[Alchemist]

I am not sure, but I think you missed my point about pressurizing from an external hand pump. My thought is to alter the base design so I am pressurizing the tank, not pressure from 243 F water. That way I have my 0.8 atm, but 205 (or whatever) brew water.

But, even so, no I am not getting too excited yet. I am sure I will hit a theory vs practice issue or two (or three )

[cannonfodder]

Misunderstood, I thought you were going to do one or the other. Actually, you could not make the pressure mod without the temp mod with the new model. If you artificially pressurize the boiler, the pstat would kick off the heating element and it would never achieve proper temperature.

[hbuchtel]

You might get good results doing the same mod cannonfodder did, but using a machine that relies on gravity or suction to get the water to the pressure chamber (La Peppina, Faemina).

Henry

[Alchemist]

Henry,

The main trick is that I already own a Gaggia Factory, like it quite a bit, and want something that I truly pull the shot with. I don't care for the pump action of the LaPepinna. I would check out the Faema, but there is this little cash flow problem.

And cannonfodder, I am slowing collecting the parts needed for your mod. Where did you get the compression fitting for holding the TC? What size was it?

[cannonfodder]

They are omegalok fittings from Omega. If you check your local hardware store you can probably find a 1/8 NPT fitting with a 1/8 tube OD compression fitting, which is what you need. I originally went with Omega because they carried BSP thread fittings. I was trying to use it for something else, when it did not pan out, I thought about this.

[DaveC]

That rambling aside, do any lever machines have heat control and/or don't over heat after a few shots? I have looked around and it seems even the much sought after Cremina has no mechanism not to over heat. It is a boiler supplying overheated "non controlled" water.

I know the new Achilles might have some group cooling plumbing, but I have not seen anything definitive yet.

When I did the review of the "Ponte Vechio Lusso 1" lever machine (I think it's called the lever Lux in the states and costs 50% more ). The UK one did not over heat and could be left on all day or pull shot after shot, as it did at an event last year.

The main reason for this was the group was not bolted to the boiler as on the Pavonis, but onto a thick metal front plate (from memory about 3mm thick) which presumably acted as a massive heat sink to prevent the group overheating, as this was able to suck heat away from the group quite effectively. This same idea seems to be used on the Izzo Pompeii lever (a big commercial lever).

Personally I thought the lever was a lot of hassle..."but you had to admire it's purity" (a line from Alien I think)

I can't remember what I wrote in the review now, it was quite a while ago, but you can find it on http://www.bellabarista.co.uk/ and if you look at the photos carefully, you can see the very thick front plate the group is attached to. I sure I have also seen the group assembly used on a number of late 60s/70s lever machines.

[timo888]

An indirectly connected group head heated by thermosyphon action, the feature of the Ponte Vecchio Lusso that DaveC mentions, was adopted also for the post-67-model Olympias, and was used in the Bezzera club machines, if I am not mistaken.

If you drop the p-stat down so that the heating element comes on at .6 bar, you may find there is still adequate steam for home-espresso duty. At that pressure, the boiler temperature is ~235°F (113°C). Depending upon the thermal characteristics of the group, the brew temperature could be in the sweet range. At 1.1 bar, the boiler temperature is ~250°F (121°C). A temperature of 228°F in the boiler is ~.4 bar.

Regards
Timo

[bill]

An indirectly connected group head heated by thermosyphon action, the feature of the Ponte Vecchio Lusso that DaveC mentions, was adopted also for the post-67-model Olympias, and was used in the Bezzera club machines, if I am not mistaken.

Also used on the currently manufactured commercial levers from Quality Espresso in Barcelona. These are branded as Gaggia, Visacrem, Futurmat, Italcrem, and Mairali.