Diagnosing bad shots on Ponte Vecchio Export

by **pangloss** on Wed Nov 16, 2011 9:51 am

I'm the proud new owner of a red Ponte Vecchio Export and Mahlkönig Vario. I've given myself a week of playing with the machine and unfortunately, have yet to pull anything better than sink shots. The shots are *extremely* sour, no matter the grind setting.

I had a friend from Italy visit last weekend and I was too embarrassed to serve her a shot! My first clue that it might not be *entirely* my bad technique is that after applying a temperature strip I picked up from Orphan Espresso, I never see the temperature strip change color. Unfortunately, the only other temperature measuring device I have is an Ikea meat thermometer. With the meat thermometer in the shot glass, I never register above 173 degrees Fahrenheit. I had thought the problem would be the group getting too hot, rather than not getting hot enough.

This is my first espresso machine, so I'm not ruling out gross user error, but if it is the brew temperature that's off, what's the process for fixing it? Or are there any other steps I can take to further diagnose?

by **aindfan** on Wed Nov 16, 2011 10:58 am

Edwin, welcome and congratulations on the new machine. Are you purging the steam wand while the machine is heating up before starting to pull shots? If not, the low temperature is caused by "false pressure" from the air in the boiler (which is always there when you close the cap after filling the machine because the machine does not have a vacuum breaker as far as I know). The next time you're heating up the machine, leave the steam valve open while the machine is heating up and close it after a steady stream of steam starts to flow from the wand.

If that's not it, I would recommend a short 1-2oz flush from the group after the machine is hot. I think 10-15 minutes is a reasonable amount of time for this machine to heat, but hopefully an actual Export user can chime in on this.

Good luck!

by **habou** on Wed Nov 16, 2011 10:56 pm

I had a OE temp strip on my PV Export and it never registered either. I took it off because it was a distraction. I think 15 min. is plenty of time to heat the machine up (I bleed the false pressure after the light blinks off and pull some water to warm the cups and get some heat into the group).

I can't help you with the other stuff.

by **pangloss** on Wed Nov 16, 2011 10:58 pm

Dan,

Thanks for the welcome. I am bleeding off the "false" pressure via the steam wand for a couple seconds after the boiler light goes off (you're right, no vacuum breaker on the Export). Like habou, I wasn't sure how to judge when I'd bled off enough, but it sounded like a couple seconds should be adequate. I'll try your suggestion of leaving the valve open as it heats up as well, though.

I have also tried multiple flushes to get a little more heat. In fact, the 173 degree measurement was only after two or three flushes. I was only in the 160s before that. The meat thermometer is a bit slow to get its readings, so I imagine the actual temperature is hotter than the readings, but I don't think it's 30 degrees off and as I understand, sour shots are a clear sign of under-extraction.

by **allon** on Wed Nov 16, 2011 11:20 pm

I'd open the valve until you see lots of steam or the pressure is mostly stable - as you bleed off the air it will drop precipitously, then start to drop slowly as you bleed off steam (as the water boils off to make more steam, lowering its temp, but keeping the pressure up). You can always try a second bleed of pressure afterwards and see if you get steam right away (or water, then steam).

by **pangloss** on Wed Nov 16, 2011 11:48 pm

For the first time I actually saw the OE temperature strip change color. According the to strip, the group hit 90C/194F.

This was after letting the machine warm up with the steam valve slightly open, two short water-only flushes, pulling a face-screwingly sour shot, another flush, and opening up the steam valve rather generously (about 20-25 mins all told).

Then I noticed the first bar of the temp strip changed color. Excitedly pulled another shot, which was still objectively pretty bad, but better than most of the previous shots--as in, it took a second, longer sip before I shuddered from the taste ;-)

Depressingly, I realize this might just mean I'm building a stronger tolerance for bad espresso, too.

Is there anything I should do with the pressurestat? I had never even registered the term pressurestat before getting this machine, so I don't even know how to get to it, let alone if and how to adjust it correctly, but shouldn't this have some effect on the temperature?

by **aindfan** on Thu Nov 17, 2011 1:01 am

If you got the machine new, I would *guess* that the pressurestat should be set properly. What does/time/number of pulls/time of preinfusion are you using when you pull your shots? High dose, coarse grind, firm tamp or low dose, fine grind, soft tamp (or something in between)?

by **pangloss** on Thu Nov 17, 2011 5:03 am

I did get the machine new, shipped from Italy.

- I'm currently dosing 14 grams of Intelligentsia in the double basket. I've gone from the very finest grind setting on the Vario to two full steps (using the coarse adjustment on the right) down.

- I've tried a fairly hard tamp to just enough to level off basket. Mind you, I only have the ill-fitting tamper that came with the machine for now.

- I've tried a few pull techniques, mostly variations on the following:

1) portafilter half-locked, then half pull of level, fully lock pf, 10 second hold at bottom, assisted lift up most of the way, lever back down again for three seconds then back up all way
2) lever down and held for 3 seconds, let it rise slowly

I think variation 1 is close to something I read peacecup trying.

I'm certain my execution is flawed in many ways, but I can't help but wonder if it's also the temperature that's a major contributing factor. I have yet to pull a drinkable shot.

by **michaelbenis** on Thu Nov 17, 2011 5:56 am

New PVs generally have the pressurestat set on the high side, though this can alter during transit, but not generally by that much. Which means a new PV is more likely to tip the balance towards the bitter end than the bright/sour end. It could be that yours is a massive exception, but I doubt it.

So, I wouldn't worry about the temperature at the moment and get rid of other variables first, all of which could be leading you to get underextracted shots.

In fact, I suspect you're right that your technique is causing problems, though I also wonder whether your grind might not be a bit on the coarse side, especially if you weren't choking the machine when the Vario was set to its finest setting. It could be that the Vario needs calibrating.

But before you contemplate that. Pull a shot in the simplest possible way to rule out technique problems as much as possible. Many of the current "additions" to your routine could be causing you to get an underextracted cup. Paring your technique down to get it as simple and predictable as possible and playing with only grind, dose and tamp should allow you to dial in a decent cup without complicating things further by altering the pressurestat setting.

Let the machine heat up until the pressurestat starts cycling (you can hear it "boiling" switching off and then kicking in, "boiling " again). Draw off false pressure and leave it to cycle a few minutes more. Get those 14g in the basket and temp with a medium tamp just using the little plastic tamper centrally to level and compact the coffee. This is less likely to mess things up than an uneven NSWE technique that aims to get all across the basket perfectly. Those deep PV baskets are pretty forgiving. Concentrate on a good balance of levelling and compressing the coffee grinds so there are no voids in the basket.

Now forget the business of locking the basket with the lever half-way down, which simply overcomplicates things for most people and makes it more likely that they lock the basket in with a jerk that disturbs the coffee much more than the lever movement is ever likely to.

Now pull the lever smoothly and firmly down. You don't have to be super-slow but as long as you don't jerk the handle violently down, you shouldn't have any problems. Now hold the lever for around 8 seconds and release. Don't just let go off the thing, but once it's taken up that initial "slack" feeling just let the spring get on with the job it's been designed for and don't assist anything - allow the machine to do it's work and try just one pull.

How does that taste? And how long did it take to extract?

On the basis of that feedback everyone here will be able to give more precise guidance.

Cheers

Mike

by **peacecup** on Thu Nov 17, 2011 8:34 am

IT IS NOT TOO COLD. The OE strips never even hit 90 C on the Export unless you overheat the group.

It is probably a grind/dose/coffee bean issue.

1. Lock the PF in all the way right from the start (no half locking - that is only for Pavoni). Then pull it all the way down and wait ten seconds. If you get coffee coming out before you let go, its too coarse grind or too little dose.

2. Let it go (slowly!). If it goes up fast and you get a lot of thin coffee its too coase/low dose.

3. If it does not go up at all its too fine.

4. If it goes up very slowly, wait unitl about half-way, then repeat. That should be best.

Old, or very dark beans will work poorly.

Making the machine too hot will make bad espresso. If it really burns your lips, it was brewed too hot.

PC


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