La Pavoni Professional Millenium - First Shot Always Cool

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mattage
Posts: 2
Joined: 8 years ago

#1: Post by mattage »

In my experience, the first shot after letting the boiler get to temperature is never good. Since the second and beyond shots always come out perfect, I'm assuming this is due to the group head not being hot enough on the first run. I have found others experiencing the same, often saying they always throw out the first. Even lifting the lever to run hot water through the group before any shots are pulled doesn't seem to heat it up sufficiently, not in comparison with actually having the portafilter attached with coffee loaded and pulling a shot. I'm assuming that this is because when a portafilter with coffee loaded is attached, the cylinder gets completely saturated with hot water for pre-extraction plus pull time.

I have seen the recommendation of letting the machine warm up for quite a while, but that seems like an unnecessary waste of energy. And throwing away the first shot seems like a waste of coffee.

I've been debating whether replacing the double spout on the portafilter with a valve would be a working solution to this problem, though that could create a clearance issue. Has anyone tried that? Or maybe cutting out a fake coffee puck out of some material with a simliar resistance? Any other suggestions?

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rpavlis
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#2: Post by rpavlis »

Both the first and third generation La Pavonis have the piston run in a sleeve, and water from the boiler comes into the space around them. If you pump the handle up and down, but not far enough to release water, you will bring hot water into and out of the space. This will heat up the group internally so that the first shot will be up to temperature. For the first generation ones it seems to take about three or four handle movements before the first shot. Bring it almost up far enough to release water on each movement. I always deliberately release a bit on the first movement to get air out of the group. With first generation machines the water movement from doing this actually cools off the boiler enough to stop hissing from the relief valve for a few seconds!

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pcroque
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Joined: 9 years ago

#3: Post by pcroque »

For the first shot in the morning, in addition to pumping the handle several times as rpavalis suggests, I heat up the portafilter and espresso cup in a pan of boiling water on the stove. The first pull can happen about 6-7 minutes after turning on the Europiccola (and stove). Might take a few minutes longer with a Professional given the larger boiler size.

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RioCruz
Posts: 631
Joined: 14 years ago

#4: Post by RioCruz »

This is clearly a case of personal preferences. The first shot on my Europiccola is the best. Just right temperature wise, smooth, creamy, flavorful. Subsequent shots (which I rarely pull) are far too hot for my taste and lack the layered flavors and nuances I have come to value.

Different strokes...that's for sure...
"Nobody loves your coffee more than you do."
~James Freeman, Blue Bottle

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drgary
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#5: Post by drgary »

+1 on doing half pumps to bring your group up to temperature. It also helps if you are measuring group temperature with temperature strips or a thermometer attached to the group. That's helpful with my 3rd generation (Millennium) machine. With my first generation machine the group has a brass sleeve and is very temperature stable and a good heat sink, so temperature strips would be sufficient with that one. I am not measuring temperature with it, but I'm very experienced with these machines and can get in the ballpark through practiced technique.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

ilker
Posts: 106
Joined: 9 years ago

#6: Post by ilker »

My first shot is always a little spongy no matter what I have tried. I think its related to temperature as well.
Normally I was doing half pumps until the group reach 93-95C and pull.
But second shot is very good and solid. I measured the group temperature after first shot, 99-100C. I dip the portafilter in cold water for 10seconds and then pull another shot. It has been working great in this way. My shots after the first always more beautiful.

Of course IR device may have some tolerance but you can just take the difference as a reference.

Then I decided to try something:
For the first shot, I do the half pumps until the group reach 100C. Then I lock the room temperature portafilter loaded with coffee and pull the shot.
No sponginess. Shots are better.

If I want colder shots, I turn off the machine before the pull, turn on the steam wand to reduce the pressure as I want and then I pull the shot.
In this way I can be more consistent.

jonr
Posts: 610
Joined: 11 years ago

#7: Post by jonr »

I'm assuming this is due to the group head not being hot enough on the first run.
Group head temp is critical and it can be too high or too low. Measuring it is the best solution. And be consistent with the number of half (actually less) pumps, the portafilter temp, the grounds temp and the surrounding air temp.

mattage (original poster)
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Joined: 8 years ago

#8: Post by mattage (original poster) »

drgary wrote:+1 on doing half pumps to bring your group up to temperature. It also helps if you are measuring group temperature with temperature strips or a thermometer attached to the group. That's helpful with my 3rd generation (Millennium) machine. With my first generation machine the group has a brass sleeve and is very temperature stable and a good heat sink, so temperature strips would be sufficient with that one. I am not measuring temperature with it, but I'm very experienced with these machines and can get in the ballpark through practiced technique.
Thank you all for the replies. I purchased some temperature strips from Orphan Espresso and have started doing half pumps (to bring the group between 100 and 105C, it seems to require about 16 half pumps) to bring the group up to temperature, which has drastically improved the first shot. Success!

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drgary
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#9: Post by drgary »

That's a lot of half pumps. You may need to set the PSTAT higher or do a brief heating flush before the first shot.
Gary
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What I WOULD do for a good cup of coffee!

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rpavlis
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#10: Post by rpavlis »

I just ran a test with a generation I machine (1964). I let it come to "full hiss" and pulled the handle carefully up to release 15 mL of water. (I measured it with a graduated measuring cup.) I made 4 "2/3 pumps". I turned the switch to "Minimo". I waited one minute. I raised the handle just enough to release a few drops of water, lowered it just a bit and attached a bottomless portafilter loaded with 13 grams of New Guinea coffee. I made the shot with an infrared thermometer "watching" the whole time, this was difficult with just two hands! As the espresso began to emerge the temperature quickly went up to around 50C. It gradually rose until when the shot was about half complete it was up to about 75-80. Then as the shot progressed it climbed and ended at 90. It may have been slightly higher if I had been able to aim the thermometer better. There was no sponginess, and the shot was perfect.

The design of generation III machines is very similar to generation I, except Generation iii has a plastic cylinder wall. Furthermore, it has a pressurestat. (I made an adaptor from brass to connect a pressure gauge to the steam wand, it always reads 0.07 mPa, 0.7 bar, when gently hissing with the switch to Minimo. I cannot use my M32x2 boiler cap pressure gauge because 1st generation boilers are the opposite sex of generation 2 and 3. It also is not possible to attach a pressure gauge to the site glass holder, because there is no opening on the holder top of many early generation I machines like this one.)

(I have always found it strange that no one seems to have ever produced brass group cylinder walls for generation III machines. I suspect there would be a good market for them. With thought one might be able to make it not only from a decent material, brass, but also improve the design. One could consider also making an oversize piston for such a system.)

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