I was having troubles, second shots not the same as the first, spritzing, spitting with naked portafilters, trying to find the right grind, right tamping everything was so close, but 'no cigar'

I had just gotten Rao's Book and was reading about preinfusion and its importance. I actually hadn't really figured out how to use the preinfusion on my Domobar manual.

I went back to the machine and realised that you needed to pull lightly on the lever, not enough to make the pump come on, just enough to let some steam wet the grounds. This was hard to measure while a 'full' portafilter, but was easy to see without any portafilter in place.

Well, to cut to the chase, I used the preinfusion for 3-5 seconds or so, and after every pull is identical and perfect and perfect tiger-stripping with the naked portafilter. No spritzing, no spitting, 25 second shot, tiger strip, everything you could want.

I am there ...... ZEN

misterdoggy wrote:I went back to the machine and realised that you needed to pull lightly on the lever, not enough to make the pump come on, just enough to let some steam wet the grounds. This was hard to measure while a 'full' portafilter, but was easy to see without any portafilter in place.

For those who are wondering what Bruce is talking about, see Is there a purpose for the E61 middle brew lever position? At the mid-point, the upper valve opens and the brew chamber gets a spritz of water (reservoir models) or is open to line pressure (plumbed-in models). For the former case, I refer to it as prewetting since there's no pressure and to avoid confusion with the E61's built-in preinfusion.

I've tried prewetting the puck on reservoir types of E61 espresso machines and really didn't notice any difference. With the plumbed-in models, it pressurized the brew chamber to line pressure, extending the E61's inherent preinfusion by a few seconds. That did seem to increase the margin of error.

My bet is that you'll discover more "secrets" over the next month or two, many of which may properly be attributed to your mastering the basics. If you haven't done so already, read Dave's Buyer's Guide to the Vibiemme Domobar Super and the associated review thread. He covers all the ins-and-outs. The Vibiemme shouldn't require any extraordinary efforts on your part; we both found it very forgiving of minor errors in barista technique (an 8.0 for its "morning after" score).

What's your pump running at (BAR)?

What's your pump running at (BAR)?

Chris,

I need to pay attention but I think it was 11 does that sound right ?

11 bar is a common factory setting for ESE pod espresso machines. Something closer to 9 bar is highly recommended. Quite surprisingly, I find this is not specifically called out in the review. Oops.

HB wrote:11 bar is a common factory setting for ESE pod espresso machines. Something closer to 9 bar is highly recommended. Quite surprisingly, I find this is not specifically called out in the review. Oops.

So I need to pay attention to what it is doing.

Does this mean at 11 the pressure is too high and forcing the water thru too fast. ....

corrected: I see where the adjustment screw is for brew pressure. If its not 9 to 9 1/2 bar I should adjust it so that it is. Are there other factors that can push the pressure higher such as too much compacting of grains, or too fine grains etc...

but first let me check it on normal operation to see if I even need to adjust
thanks for this important heads up

Well I just ran the brew cycle with a double basket, tamped at 30lb (espro) preinfusion waited a minute then brewed and the bar meter went to 12 bars during most of the brew cycle.


Dan,

So 12 Bars it is.

Am I to understand that it is too much and I have to adjust down to 9 ??

How can the factory set it so different than what you are suggesting ?? Hmmm

Please I need to get this right before fooling with it thanks

This would explain not only some of your problems but why you're seeing improvement through manual preinfusion.

Suggest reducing down to something between 8.5 and 9.5 BAR.

Search on 'Vibratory pumps' and 'OPV' in the FAQs and Favorites, you will find all the information you need.

I read the manual I that I think was written by Randy on LaVibiemme and I tried running the blind portafilter on the machine for 20 seconds to see where the true brewing pressure was and it went to 13 and stayed.

With a normal brew in the basket it went to 12 so something is wrong

I read in the manual there is a screw you can turn to dial down the brew pressure and you do it while the blind filter is on to get the reading moving it in small increments

I guess I'm not there just yet

Vibe pumps run about 0.5 to 1 bar high when using a blind portafilter. On the DomobarSuper it is a half bar. Take the shell off, put the blank basket in the portafilter, turn the power onto the first notch (power but no heat) and turn on the pump. Turn the OPV down until you are getting 9 bar on the gauge. Dont run the vibe pump too long, 60 seconds or so. Once it is set, check the pressure again 2 or 3 times to make sure it does not drift, then put the shell back on and heat it up. That should get you between 8.5 and 9 bar on the brew pressure. My test machine was already set dead on right from VBM.

From the Bench review...

The OPV (Over Pressure Valve) is located in rear of the machine. For those of you new to the espresso machine world, the OPV controls brew pressure by venting excess pressure from the pump and returning the water back to the water reservoir. The Vibiemme has one of the heaviest OPV's I have seen. Once the outer shell is removed, you can access the adjusting screw through an opening under the water reservoir. The angle is a bit awkward but still usable. It would be easier to access if the opening was cut a half inch lower. To adjust the OPV, turn the screw counterclockwise to lower and clockwise to increase.

Dave,

Thanks so much. I have jusst about got it set. Working on it while we speak.

The only difference is in "your" picture the screw is pretty far in. On my maching the screw is actually backed out a bit to get it down. Does that matter ?

I got it set at 9 spot on.

When it was 13 blind filter it was 12 at brewing

So now this will change from probably 9 bling to 8.5 brewing

This probably means all my work to this point has to be redone. Grinds will have to be set differently for a different brew pressure.

Otherwise I should be able to tackle the shots easier with less pressure (hopefully)

I'd aim for 9.25 to 9.75. IMO 9 is just a tad low. It's just personal pref.

Once you're done, mark the OPV position with a felt pen so you can return should you ever need to R&R the OPV. They sometimes have a tendency to start squealing after a few months.

cafeIKE wrote:I'd aim for 9.25 to 9.75. IMO 9 is just a tad low. It's just personal pref.

Ike

corrected

I set it to 9.8 (blind) but it drops to 8.8 when I brew (cold). which one is true (blind or brew)
and in the manual it says the gauge usually er's to a higher number

I will have to grind finer to make this work, but everything will really fall in to place now

If I was close with 12-13 bar (in my mind huh) then with 9 bar it should be heaven

thanks to everyone on the forum so much muchas gracias, molto grazie, merci mille fois !!

PS I wonder if the factory could set the pressure to 12-13 in error, then it is possible that other things have been set wrong like the temperature needs checking too ?

Since the adjustment on the brewing pressure I hear the heating element clicking on a lot could be my imagination and paranoia

9.8 on the gauge while brewing would be my choice.

It's not set up 'wrong' per se, but deliberately :

cafeIKE wrote:The pressure is set Hi to avoid "My machine doesn't work" tech calls.
At 11 bar, with commercial coffee or sub any grinder we'd be caught dead with, you'll always get something in the cup.

It's kind of like buying a new target pistol. Those that know what they're doing will sight it in.
Those that don't can't hit the broad side of a barn unless they're standing on the latch.
...from Brew pressure and its effects on espresson.

On a 110v machine in SoCal, normal duty cycle is about 10 in 150 : click on for 10s, click off for 140s, click on for 10s, click off for 140s.

On a 110v machine in SoCal, normal duty cycle is about 10 in 150 : click on for 10s, click off for 140s, click on for 10s, click off for 140s.

I'm not following the jargon ? 10 in 150 or off 10s 140s ?????

When using less pressure lets say 9.8 brew, does that mean the grains need to be finer ? I noticed the grind that worked well at 12 gushed thru a 10 ?? I would have thought it would be the opposite since less pressure is pushing thru, but it has been the opposite ?? Its all very curious

More pressure compacts the puck more, ergo less flow.

The light for the heater is on for 10s
The light for the heater is off for 140s
-----------------------------------------------
The total time from on to on is 150s

Duty cycle is 10 in 150

Everything is different with a 9.8 Brew pressure than it was with the 12 brew pressure

I have to apply everything I have learned to this point with a fresh view

The taste is a bit different too. I'm getting there still. Will I ever arrive ?