lattelover wrote:...split from Some thoughts on heat exchanger vs. double boiler espresso machines by moderator...

I was ready to pursue buying a double boiler because of the milk frothing/steaming capability and lower learning curve, but then I read a blog by Kat at Seattle Coffee Gear dated 3-1-09, around the same time that this forum discussion began, and also I talked with her on the phone yesterday. She said that the Italian espresso machine makers stopped making double boilers for commercial use in the 1970's and since then have been making them only for home use. Also, she talked about the "dead" water, or residual, that sits in the double boiler until the next batch, whereas the heat exchanger is constantly cycling fresh water through the siphoning system. This is not the same as having spring water sitting in plastic jugs, because the water can or does interact with the boiler. The link to her blog is below. Of note, Seattle Coffee Gear sells both kinds of machines, with the idea that there's a home for each.

I'd appreciate any comments anyone can offer.
Ann

A lot of science and techno-expertise here! I'm impressed with Ian's "cheap and cheerful" TDS testing and the other helpful info. on descaling, leaching, etc.

Also, thank you, John, for clearing up the "cross posting" issue. Hope you know I was speaking tongue in cheek about the "kinky" stuff. In the end, I missed what you meant completely, so good to have it straightened out.

With regard to the equipment, two aspects are sticking out for me:

1) COPPER: Newbie though I am, I do feel concerned about the copper boiler/copper tubing issue. Where I live we have very hard water, a water softening system is required, and the plumbing in the area is generally being switched over from copper pipes to something like PVC because the copper deteriorated over time due to the hard water, maybe even with softeners. However, it looks like it's hard to get completely away from copper in espresso machines because even if the boilers are stainless, the tubing seems to be mostly copper.

2) SMALLER BREW BOILER CAPACITY: I don't know how easy it is to empty the brew boiler when not brewing, for the purpose of putting in fresh water, and I also don't know how much of an effort it is to fill it if it runs dry in mid-brew. If neither of those is a major effort, then I would think the smaller capacity brew boiler would be a good idea because the water is being changed often enough.

Right now, I'm leaning toward double boiler machines rather than HX. The GS 3 and Synesso are out of my price league, so I'm considering the Mini Vivaldi II (group boiler 0.4L) or Alex Duetto (group boiler 0.8L). The Duetto has stainless steel boilers but copper tubing. I don't know what the Mini VII has.

Any comments are welcome!

The brew boiler is continuously filled. If it runs dry, the element is toast.
It's a PITA to drain any boiler without a dedicated tap.

Thank you, Ian. Is a dedicated tap an add-on feature or does it come with the DB machine? If only some machines, can you tell me which ones?
Ann

The Vivaldi S1V2 & Mini both have a drain plug on the steam boiler. The .45 litre brew boiler has a screw on cover & mounts horizontally but there is no need to drain it as it is constantly being refreshed through normal use. The Mini uses a stainless steam boiler & the S1 a chrome plated brass steam boiler. I believe both use brass brew boilers.

JohnB, thank you. That's great info. Also it helps me with my question list for other brands.
Ann

On the Vivaldi S1V2 clearly the brew head that forms the front cover of the brew boiler is chromed brass, however I'm not sure about the body of the brew boiler; it looks like it could be stainless steel?

Well, I had a good chuckle over the "Schechtermatic" and his "shnozzola" up at 4:18 AM (so says the post). Given John's post at 12:30 AM, this recent part of the discussion has gone on nearly all day and all night, with the exception of 12:30 AM to 4:18 AM.

I did have one year of undergrad physics, but it was sometime ago, so although I have great respect for the thermodynamic discussions on boiler shape and size, I'm going to focus on my comments and questions on materials used and boiler position (vertical vs horizontal). Although, I suspect some of them may end up having thermodynamic answers anyway!

Before 12:18 AM and after 4:18 AM, I read three of the "closer" looks on Bella Barista, which are in-depth technical write-ups of UK-owned machines, with some personal review thrown in. You probably all know about these closer looks, but they were new to me. They are on the Alex Duetto II, Alex Duetto, and La Spaziale Vivaldi MKII. The links are below. My page number references (below) are to those articles. The Duetto and Duetto II articles appear to be nearly, if not exactly, identical

As far as I can tell, the author and date written are not revealed. The Duetto article says the machine was manufactured in May 2008; the other two don't say. I don't know how much the Euro machine issue changes things for us in the U.S.

Here are my comments, confusions, and questions; the section on materials for the boilers (under #1) relates to comments by MDL and JohnB:

1) MATERIAL USED:

BOILERS:

The claims for both the Duetto and Duetto II are stainless steel outside and inside (p. 1 and 6 for both articles). However, later I find the statement that the custom boilers are both made of thick COPPER (p. 4 and 7 for both). The MKII has nickel-plated steam/HW and brew boilers (p. 6).

Duetto II has "factory installed boiler insulation" (p. 1); as far as I can tell, the Duetto doesn't have that. I don't know about the MKII.

TUBING:

The Duettos have all copper tubing (p. 4). The MK II has plastic tubing for "high pressure water, steam and hot water". The author comments on my concern in my earlier post about copper tubing, stating "...copper can become a little brittle as the pipes age and corrode, also the plastic can be moved out of the way during maintenance and connectors are easy to refit" (page eight). He/she goes on to propose an experiment using plastic boilers for steam/HW but not brew.

MY QUESTIONS:
a) What is this about, with the claim of stainless inside and out, followed by copper boilers?
b) What about copper vs nickel-plated? Any significant difference?
b) What happened to brass, which I read somewhere has the best heat-holding capacity? Too expensive? What about stainless steel boilers, one or both?
c) How important is having the boiler insulation?
d) How important is copper vs plastic tubing?

2) POSITION OF BOILER:

The MKII has a horizontal-positioned brew boiler (p. 5). The Duettos have both boilers vertical (p. 4-5, both articles).

MY QUESTION:
What's the difference? Is it significant?

3) PLUMBED and NON-PLUMBED:

Both Duettos appear to have a switch to change from plumbed to tanked (p.3 of both articles); I think the MK II is only non-plumbed, but I'm not sure.

MY QUESTIONS:

a)I thought the Alex was strictly non-plumbed. Am I wrong?
b) I'm renting a house; if I have a plumbed-in machine, can that be reversed if I move, without causing damage to the existing plumbing?

Lastly, I hope the length of this post and the number of questions is not a deterrent. Feel free to pick and choose.
Ann


LINKS:

1) MKII:

http://www.bellabarista.co.uk/pdf/Laspa ... lookv4.pdf

2) Duetto II: (2 versions)

http://www.bellabarista.co.uk/pdf/IzzoA ... lookv4.pdf

http://www.bellabarista.co.uk/coffeemac ... -water.asp

3) Alex Duetto:

http://www.bellabarista.co.uk/pdf/IzzoA ... lookv5.pdf

The Vivaldi MK2 review is talking about the S1V2 which is a rotary pump plumb in only machine as opposed to the vibe pump, pourover Mini Vivaldi. The S1 uses nickel plated Brass boilers, not copper or stainless. The horizontal brew boiler is part of the La Spaziale proprietary group head design whereas the other DBs in this price range use the generic E61 grouphead.

The Vivaldi steam boiler does not come insulated from the factory. I insulated mine & achieved a 42% reduction in heating cycles so I would personally recommend it. The Vivaldi uses some copper & some plastic water lines. The lines that you might have to remove for service are typically plastic which makes it much easier to move them out of the way.

to JohnB: thank you for this VERY quick answer. And thanks to Dan for the VERY quick moderation and getting this discussion settled in its right home.

Back to JohnB: I'm glad you cleared up my confusion---I somehow thought the "M" in MKII was for Mini. So now I'll have to check out the Mini with all those same questions in mind.

Two questions for you:

1) could you say how you insulated your Vivaldi and what you used? A 42% reduction sounds like a big deal to me!

2) What's your opinion of the proprietary horizontal brew boiler---does it make a significant difference and if so, what is the difference?

Again, thanks,
Ann

Ann, you're getting lost in the minutiae, none of which matter a whit when it comes to espresso.
A recent study found mercury contamination in ALL samples of fish taken from 300 lakes in the US.
Mercury found in all fish caught in U.S.-tested streams
Breathing the air in any metropolitan city probably shortens your life more than 10 espresso per day from a copper boiler.

The EU, of which Italy is a member, banned nickel from many products.
My Vibiemme HX has a nickel plated boiler. New ones don't.

Any machine you are mentioning will make great espresso if you are up to the task.

As is oft repeated : The grinder makes espresso. The machine pushes hot water through it.