La Pavoni refurb - still not working - Page 2

A haven dedicated to manual espresso machine aficionados.
RobAnybody

#11: Post by RobAnybody »

fieldp wrote:.I have a Peru Gesha espresso blend from Friedhats which was roasted about a two week ago. So will try that. It is quite light looking. Not oily on the outside, so maybe grind a bit finer.
I find it helps to aim for a 1:3 ratio with lighter roasts to balance the innate acidity. My approach for that is to load ~12.5 grams and do a few small pumps (about 5) during the pre-infusion. You'll hear air leaving the grouphead and feel the lever action stiffening due to more water in the grouphead. Generally I get about 34-36 grams of espresso doing that.
fieldp wrote:I got some tooth picks as a (very) crude temporary approach to try.
this should also work, keep a good eye on the grounds to see how much you need to stir to break up the small clumps.
Best of luck!
Rob
LMWDP #647

fieldp

#12: Post by fieldp »

A quick update.

Tried again with fresh beans. 5 clicks on the Commandante. This is way finer than they recommend. 30 minutes warm up. Let steam bleed. I did not see a pressure drop though. Well hardly any. Not sure if that means anything. I bled the steam through the wand for about 10 seconds. Then flushed two espresso cups of water. Did not see much pressure change at all. I just stayed around 1 bar. The pressure gauge was fitted when it was serviced so I would like to assume it was done properly. Or maybe a different issue. I think they cleaned it but maybe is worth another descale. Citric acid and warm water? Wonder if a blockage could cause water not to come up properly. The first 2 cups of water I flushed seemed to work though. I left the portafilter off and water came out the shower head when the lever was right at the top. Water only comes out when the lever is 100% at the top.

When I tried the late lock-in, I got no water even at the very top and with pressure gauge showing 1 bar. I had to re-lift the lever twice to get anything coming through. Maybe I choked it but after the second lift there was only moderate pressure. In the eventual shot, there was almost no crema. I know these beans are pretty fresh as when I opened the jar they come in, the little seal under the screw top actually popped off. I understand that is c02 and in the jars they use, because there is no vent, there would be some pressure.

I noticed the puck was a bit cracked. Also it seemed dry. Not sure what that means? I tried really carefully to break up clumps, get it level and tamped moderately. I see lots of people saying 20Kg of pressure but no idea how to measure that. Short of putting a 20kg kettlebell on the tamper. It's an idea actually...

The shot had an extremely acidic finish. Maybe not quite so bad as the previous but really pretty bad. But again, it could be me and the method. I will try a few more times. I ordered a digital thermometer. Will have it in 2 days. Will know more then and do some experiments. Agree if it's not getting up to temperature, nothing is going to work properly. Also no idea how to fix that. But right now, need data as just guessing at the problem. I have now got a service kit with a full set of gaskets. So if nothing else works, I am tempted to take it apart and see if I can see any wear. I am not super confident mechanically but have watched some videos and it does not look too difficult. There should not be any wear as it was only serviced a few weeks ago. Unless something was missed in the service. Again I am only guessing. I have no reason to think there was a problem with what they did.

I am only using tap water. Not filtered. Will do that, but not sure this is likely to be a factor?

Ideally I could find someone with a similar machine/grinder and could give me a configuration that works on theirs. I am quite happy to order a specific coffee. Just anything to help rule out issues.

One additional question, when the green light goes out, does that mean it thinks it's up to temperature or up to pressure or both?

Thanks again for all the advice.

Paul

User avatar
guijan12

#13: Post by guijan12 »

fieldp wrote:.....

When I tried the late lock-in, I got no water even at the very top and with pressure gauge showing 1 bar. I had to re-lift the lever twice to get anything coming through.

....
This sounds like a technical issue with your machine.
It can be scale or something not fitted well after the cleaning.
Water should start running with the lever about halfway up.
Regards,

Guido

RobAnybody

#14: Post by RobAnybody »

Hi,
fieldp wrote:30 minutes warm up. Let steam bleed. I did not see a pressure drop though
Did you bleed the pressure just after the machine reached pressure or after 30 minutes?
Your version is equipped with an ani-vacuum overpressure valve,
Which means it will vent some steam when coming to pressure, this can be enough to prevent a massive pressure drop during the bleed. Also if you bleed after 30 minutes the cold headspace will also have heated up a bit more so you'll get less of a drop.
fieldp wrote:When I tried the late lock-in, I got no water even at the very top and with pressure gauge showing 1 bar. I had to re-lift the lever twice to get anything coming through.
You mean with the portafilter locked in?
If so, you have fine ground fresh coffee in a tightly packed puck, this will hold the water back quite some time. I've even had the lever up for a few minutes in a test before any coffee came through the puck without applying pressure.
fieldp wrote:Maybe I choked it but after the second lift there was only moderate pressure. In the eventual shot, there was almost no crema
Almost no pressure in the first part of the pull? This means you'll have to do a fee more wiggles at the top to get the air out of the group. (You can search the forum for 'spongy pull' to get more tips and tricks on this)
fieldp wrote:I noticed the puck was a bit cracked. Also it seemed dry.
the dryness happens if the last bit of your pull is mostly air
fieldp wrote:I see lots of people saying 20Kg of pressure but no idea how to measure that.
Try doing the tamping on the bathroom scale to get a feeling for how much pressure that is. People also did this trick to feel how hard you have to pull the lever to get close to 9 bars of pressure.
fieldp wrote:The shot had an extremely acidic finish. Maybe not quite so bad as the previous but really pretty bad. But again, it could be me and the method
Light roasts have more acidity than darker roasts, if it is just at the finish, you probably have a cup that is higher than it is wide.
This prevents mixing if the espresso while you drink it resulting in a physically layered shot. (See also Are cup size and shape too often everlooked factors?)
To prevent this you can stir or swirl the cup before tasting.

Again you may have to get the grouphead a bit hotter, try one or two lever strokes without letting water out before you raise the lever to lock in, this will raise the grouphead temperature.
fieldp wrote:I am only using tap water. Not filtered. Will do that, but not sure this is likely to be a factor?
Not likely unless the water has a strong taste by itself. It will mean you have to descale the machine much more often (depending on the hardness of your water) if you want to change that search the forum for rpavlis water (a recipe using distilled water and sodium bicarbonate to create neutral buffered water with minimal hardness)
fieldp wrote:One additional question, when the green light goes out, does that mean it thinks it's up to temperature or up to pressure or both?
On a pressostat regulated pavoni (such as yours) the light goes out when the pressure setpoint is reached, the heating element is then switched off. Boiler pressure has a linear relation to the water temperature, if the air above the water has the same temperature (hence the bleeding of pressure at the start).
Cheers!
Rob
LMWDP #647

fieldp

#15: Post by fieldp »

Hi,

Thanks again for the very detailed help and pointers. I have now gone down the threads on spongey pulls and definitely have some things to try here. I need to read it all again, but think I am getting the idea.

The digital thermometer should be here tomorrow so I can see what is happening with temperature in the group head.

I was smacking my forehead when I saw the point about the bathroom scale for tamp pressure. Great idea. Will try it.

I have tried stiring the shots but it did not seem to help. Interestingly, on some I could actually see the oil floating on the top. Or assume that's what it was. Didn't taste good though.

I am using quite a wide cup. 67mm across at the widest point. And about 46mm deep. I have also tried a narrower cup which is 57mm across but more like 52mm deep.

So I am going to try the various multiple pull / heat up suggestions and see what happens.

I just want to make sure I want to understand the principle though. Is the objective to get a layer of water vapour into the puck asap and then to force that through the puck? Or do I actually want water vapour above a small pocket of air because the air creates the resistance? I thought it was the former, or otherwise I am pushing air through and as mentioned, I would then get a dry puck which is often what is happening. I understood that the small pumps (aka Fillini move?) will get air out and this is good.

A related question but I wonder if his is straying into a whole other area; my understanding is coffee grounds absorb water at a ratio of about 2g of water into 1g of coffee. So they swell? So would it follow that a coarser grind should be left to pre infuse a bit longer so everything swells and becomes air tight? Or does the water just flow through? Or is the point to modulate the pressure to get the swelling? I am just thinking that I only started to get resistance around 5 clicks on my Commandante and most other people are saying 9 or 10 work. Though my problem could still be air and temperature so I am not going to mess with another variable yet.

Thanks so much and I am quite in awe of the experience and expertise out there. Thank you. I will persist.

Paul

SeekingGodShots2

#16: Post by SeekingGodShots2 »

Not sure if it's covered, but the gasket that keeps the shower screen in place is "flat side down" and the curved side is oriented up to the grouphead.
LMWDP #548