Woot! Vibiemme Domobar Super & Cimbali Max Hybrid have arrived - first impressions and questions

[Bex]

I am in espresso heaven.

As documented elsewhere, I upgraded from a Gaggia Carezza and MDF to a Vibiemme Domobar Super (Manual, black) and La Cimbali Max Hybrid. The difference is....almost indescribable. Leaving taste aside for the moment, these new machines are light years ahead in terms of design asthetic and, more importantly, ease of use. I am absolutely glad that I spent 3 months cutting my teeth with the Carezza, as the basic skills are obviously transferable and I knew off the bat what I needed to do and what results I wanted to see. The first shot from the new combo was - while far from perfect - better than anything I've pulled to date. The nagging bitterness that I'd never been able to eliminate on the Carezza was gone. My taste is telling me that I'm still brewing too hot, though, so I've got a lot of tasting and trial and error ahead.

First thoughts, impressions, and also a question.

Questions:

Question: the VBM's brew pressure never gets above 6 bar, even if I'm using the blind basket to backflush. My assumption is that I need to open the machine and increase the brew pressure, but never having owned a machine like this, I'm a bit lost - Dave's review suggests that I'd do this at the OPV near the resevoir, and the owner's manual shows a picture of what to look for. Am I on the right track? I have an email in to 1st Line but would appreciate hearing from the community here, too.

Question 2: when backflushing (something else I've never done, since Carezza didn't have the capability), I thought the water would come out into the drip tray, but that isn't happening (until I end the backflush). Am I missing something, or is this normal?

Impressions:

Max Hybrid: Wow. Mine arrived set to 5.5 on the dial. I dialed it to 5 before grinding the first time. It takes only around 10 seconds to grind enough coffee to fill the PF - a huge change from the 25+ seconds for the MDF. The grinds come out of the doser looking near perfect; they are fluffy with no clumps. Level, tamp, and I get a perfect puck, and one that doesn't show any evidence of channeling after the shot (no tell-tale pinholes). At 4.5 I only get a trickle from the machine, and at 4.75 I'm getting less than ristretto volume. The 5 setting is pulling close to 1.5 oz in 30...but these shots run longer before blonding. I think all of this will change when I fix the brew pressure on the VBM.

VBM: Man, I love the look of this machine. Set up is easy and, with the three way power switch, first time power-up is worry free. It's got the flow restrictor in the HX thermosyphon that Dave mentions in his review, so I see very little if any flash boiling when flushing water. My current routine (suggested by Dave) is flush about 4 oz of water when the machine's been idle, then prep the PF, flush a bit more, and go. The shots look great when they are pouring - none of the blackness that would characterize the start of my Carezza pulls - and look great in the cup (no more light crema). Taste is great, but I know it can be better. I need to sit and experiment with flush amounts to get the shot temp a little lower.

As for steaming, this thing is a monster! It takes no time to steam; gone are the days of steaming 6 ounces for nearly a minute and running out of steam before the temp hits 155. On the flip side, the first time I steamed milk, I started with 6 oz in a 12 oz pitcher, and the milk overflowed the pitcher before the temp got to 150!!! The consistency of that milk was really nice, though. I've gotten closer to microfoam but I'm not there yet. I have to figure out how to stop the stretching of the milk so that the volume doesn't get out of control like something from a cartoon.

Overall, incredibly happy with this kit. Thanks for all your help.

[cannonfodder]

You will need to remove the 3 screws on either side of the case. The shell will then come off. Under the reservoir, there is a square cutout, inside that cutout is a big brass fitting with a slotted screw. That is the OPV adjustment. You will need a large slotted screwdriver. Make small adjustments, no more than a quarter turn if that, then plug the machine back in and turn the power switch to the first setting (power but no heat) and check the pressure. Readjust as necessary.

Backflushing, nothing will exit into the drip tray until you lower the lever, then woosh! Only run the pump for 4-5 seconds then lower the lever.

Milk frothing, only stretch the milk to 90F, and then put the tip down to where the tip and tube meet so you are not mixing in more air. Let it swirl, when your thermometer hits 135'ish stop. It will carry over to 150. If you steam to 150 on the thermometer the milk will carry over to around 160-170.

[Bex]

Fantastic - thanks very much.

[Bex]

Man, turning that OPV screw is difficult, as it sits below the opening. Took awhile before I could find something angled enough to reach in and turn it.

But I'm getting 8 bar now. Should that be good enough?

[erics]

Firstly, congratulations on your new machine and grinder. It is a very impressive package.

Espresso machine pressure gages, whether they be boiler pressure (0-2.5 or 3.0 bar) or brew pressure (0-16.0 bar) are both relatively inexpensive and relatively inaccurate when compared against a name-brand gage of the same size. I say this after comparing various machine gages against those with known (at least published) accuracy specifications.

When you adjust the OPV screw such that the machine's gage reads ~8.0 bar during blind filter runs, that is the maximum you will ever see on that gage no matter how fine you grind the beans. So, assuming that your 8.0 bar was measured during a blind filter run, I would say you should boost it up to around 9.50 bar as I see about a 0.5 bar differential between blind filter pressure and pressure during typical double shot flows.

And, after you make this adjustment, be prepared to grind those beans a little finer.

[cannonfodder]

I normally see a 0.5 drop in pressure with vibe pumps when comparing the blind to puck pressure. You may want to go a little higher, how high is personal preference. Set it, use it for a few days, change and repeat to find what you like.

[Bex]

Thanks, guys.

I confess I'm not eager to open it back up - it's a beast to move around, and the screw is very difficult to access & turn. Plus, there was one position of the screw where when I pulled a blank shot, the brew pressure gauge would go crazy, going up to 6 bar, dropping, back up, dropping. Happened a couple of times as I tried to find the right setting, always in the same position.

Still, it's probably a little low based on what you're saying and what the manual on the CD says (1st Line put together a huge manual on a CD, and I didn't realize til today that it was a different manual than the skimpy thing VBM sends out). The 1st line manual suggests that the brew pressure gauge is reading 1 bar higher than actual pressure.

My first shot this morning hit 8 bar. A later shot was actually closer to 10. Odd. The machine had been on for about 40 minutes for the first shot, and closer to 2 hours for the later shot.

[erics]

My first shot this morning hit 8 bar. A later shot was actually closer to 10. Odd.

Not only odd, but NOT RIGHT. As I said before, , with a properly operating OPV set with a blind filter, the gage on the machine reads "X". There is no way, to the best of my knowledge, how you can ever get above "X" when pulling ANY kind of shot. Now, very gradually over time (months & months), "X" will decrease a couple of tenths due to the spring losing some "umpf" and the valve/valve seat wearing a little but you would hardly notice it.

See Dave's review thread on the Vibiemme - buyers-guide-to-vibiemme-domobar-super-t4019-100.html and look on page 6 - Randy Glass brings up some important facts on the OPV spring.

[Bex]

Hrm.

I will take notes on the pressure for the next several shots. Randy's description of replacing the spring is a bit daunting, but there you go.

[cannonfodder]

Hmmm. VBM did have a production run with bad OPV springs. Their supplier supplied some wimpy springs. The pressure will act erratic and wander. The OPV will be next to impossible to adjust if you happen to get one, which would be disappointing to say the least. It is an easy fix, you just unscrew the OPV , put in the new spring, and then screw the screw back in. You may want to drop Jim an email about it and have him ship you a replacement spring, if that is what is wrong, and it sounds like it may be.

[Dogshot]

...or your 8-bar shot was not ground fine enough to allow the OPV to become relevant. Maybe you changed your grind after the 8-bar shot, and now that is was finer, the OPV's pressure limiting effect came into play at 10-bar. In other words, it is possible that you reset the OPV to 10-bar.

Mark

[cannonfodder]

The best way to diagnose the issue is with the blank basket. Check your pressure as it sits then pull the covers off, make a small, very small, like the width of the slot on the OPV screw, power it up and do a backflush to see where the pressure runs. Then make another very small change and check the pressure again. If it swings wildly from say 7 bar to 11 bar instead of the 8 to 8.05-8.1 that the adjustment should have made, you have a bad spring. You will also hear the OPV start to open early. Instead of a steady hum up to pressure, you will get a chatter sound and the pressure gauge will bounce a little as it swings up to pressure. Don't mistake it for the normal dip when the heating element cycles. Another possibility, the boiler fill kicked in while pulling a shot. That will cause the pressure to drop drastically, then shoot back up to full pressure.

[Bex]

I think I'll call Jim today. Log of the last 5 shots + a couple of blanks:

Last night:

Blank 1 - 7 bar
Blank 2 - flies over 12 bar
shot 1 - 8 bar
shot 2 - 8 bar

This morning:
shot 1 - 7.5 bar
shot 2 - 7.5 bar
shot 3 - 7.5 bar
blank 1 - 8 bar

When I tried to adjust the screw Tuesday, it was incredibly difficult to make the screw move. (which is what worries me about replacing the spring....maybe I can find a big slotted screwdriver that has a 90 degree turn at the end, that would make it a lot easier)

[Bex]

Just got off the phone with Jim. He was incredibly helpful - says that the issue is a handful of the black units, and he's getting a new spring out to me. The recommendations here on the good service from 1st-line definitely seem to be well-deserved. Jim also walked me through how to remove the reservoir holder-thingy, so that should make this repair easier.

On the good news front, I'm starting to get the hanging of steaming the milk. Today's cappa was the best I've ever had. I am not getting perfect microfoam yet, but I am getting milk that is consistent, instead of hot milk pouring out from below a cap of foam. Just need to get rid of some big bubbles that are forming right at the end of the process, and who knows, maybe I'll even try latte art.

Thanks for the diagnostic help, guys.

[cafeIKE]

The OPV mount is a bit flexible, so with the machine COLD, you can reach in from the side to move the OPV slightly to make adjustment easier. Use a HUGE screwdriver with a blade tip almost the size of the OPV adjustment slot.

When changing the spring, place a folded towel under the machine and another under the OPV to catch the water.

It's probably a good idea to get some Lubrifilm to lubricate the OPV. After a few months of use, the OPV in my machine started screaming like a banshee and the pressure would vary about ~1bar when the heating element engaged. After a lube job, the OPV has been silent for over a year and the pressure barely dips when the heating element engages.

[mhoy]

...It's probably a good idea to get some Lubrifilm to lubricate the OPV. After a few months of use, the OPV in my machine started screaming like a banshee and the pressure would vary about ~1bar when the heating element engaged. After a lube job, the OPV has been silent for over a year and the pressure barely dips when the heating element engages.

CafeIKE:
Could you add some detail on how to do this?
Thanks a bunch
Mark

[cafeIKE]

Perusal of this Coffee Time OPV PDF should give you all you need

[Randy G.]

Thanks, guys.
I confess I'm not eager to open it back up - it's a beast to move around, and the screw is very difficult to access & turn. Plus, there was one position of the screw where when I pulled a blank shot, the brew pressure gauge would go crazy, going up to 6 bar, dropping, back up, dropping. Happened a couple of times as I tried to find the right setting, always in the same position.

One of the things I originally mentioned was that there should have been an access port for the OPV at the back of the machine so the case would not have to be removed.

It sounds like you need to replace the OPV spring. I think you may have one from the bad run we experienced. The replacement, as described in my post concerning the procedure to change it out, your symptoms sound just like what I experienced. The correct spring should give silky-smooth adjustment when viewed on the gage. it is an easy matter to change it- not much more difficult than it was to adjust it. Just turn the adjustment screw all the way out, pull the spring, replace it with the new one, and replace the screw... basically.

Still, it's probably a little low based on what you're saying and what the manual on the CD says (1st Line put together a huge manual on a CD, and I didn't realize til today that it was a different manual than the skimpy thing VBM sends out). The 1st line manual suggests that the brew pressure gauge is reading 1 bar higher than actual pressure.

Hope you found the manual useful and informative. The brew pressure of which that speaks is the pressure at the coffee. I have my OPV set at about 9.5 to 9.75.

[mhoy]

Perusal of this Coffee Time OPV PDF should give you all you need

Wow, great article.
Thanks,
Mark

[Bex]

Thanks, guys. The manual on the cd was great, Randy - everything I'd want to know about the machine.

This morning's shots: shot 1 - 7 bar, shot 2 - 7 bar, shot 3 - 8 bar, blind 1 - 8 bar, blind 2 - 10 bar.

Notwithstanding, they tasted great. Though the Max Hybrid is a big contributor that, really. Between the MH and the features of the VBM (including the flow restrictor), this combo is almost fire-and-forget in its ease of use. Flush a cappa cup full of water, prep PF, pull shot, enjoy. And the milk drinks, geez, to be honest, I never knew what I was missing before. These cappas are heavenly.