I suppose I have experienced the same thing - or should I say, "lack of the same thing". I almost always open the steam valve on my Gaggia Factory for a short while (20 seconds or so...) into a cup of water to avoid making a messs, upon first heat up. I do this to "release the false pressure" - but I do it simply because I've read here on the forum and elsewhere to do it. Frankly, I've not noticed any indication of false pressure before doing it, while doing it, after doing it, or when I've not done it... In particular, I've not noticed anything "different" during the duration of the release to indicate a change in what's being released - e.g. no sputtering before the steam begins to flow, etc... the steam release "behaves" the same from start to finish during the release for "release of false pressure" and seems to be the same as when I release steam for steaming milk after pulling a shot. Similarly, there seems to be no real change in the reading of the pressure gauge, other than the same sort of slow & even minor drop in the needle reading while the valve is open - just as when steaming milk.

Is it possible that the need for "release of false pressure" has been overstated in the literature, and that some machines are more prone to needing a release of false pressure, others less so - and some in no need of it at all?

mindless_fool wrote:hi uscfroadie, thanks for the info, what do you mean by flashing? if i flush i seem to get steam with the water, is that what you mean?

Alex,
Yes, the steam you mention is flashing - actually water that is way to hot. When the water even spurts out you are seeing signs of water that is too hot. This can be seen by watching a "HX water dance" video on YouTube. Sorry, I'm at work and cannot send you a link, but a simple search should yield a few results.

r-gordon-7 wrote:Is it possible that the need for "release of false pressure" has been overstated in the literature, and that some machines are more prone to needing a release of false pressure, others less so - and some in no need of it at all?

Very well could be. I bleed off a bit of pressure that results in a little bit of wet steam upon initial opening of the wand but is not present from then on.

I think a good way to test for false pressure is to not bleed off the wand and perform the styrofoam test. Mark down the registered temp of the pull. Quite a while later, after the machine has sufficiently cooled, perform the same test. This time bleed a little bit of pressure out of the wand and allow it sufficient time to rebound. See if the resulting temp changes from performing the same test.

I would perform this test, but I am currently in Iraq and do not have the machine with me. Might have it sent over though as the coffee here is as bad as I remember.

what should i do so i dont see that flashing. should i lower the pstat if it means the water coming out is too hot?

There is nothing that can be done to eliminate the flashing. Even at .6 the boiler pressure makes the water boil at temps that will create flashing once the group gets hot enough. Any lower than that and you won't get much milk for steam, and will take a while to get water into the group when you lift the lever.

This why I suggest brewing with a cooler group. I don't flush or prewarm the group at all anymore on my closed-boiler spring lever (PV).

Also, different espresso blends are blended and roasted to be brewed at different temperatures. Perhaps with the Pavoni its best to use blends designed for higher temps?

I still seem to get high temps with it at a cold start, I wonder if it's cause mines a frankienpavoni, it's a pro body (larger boiler and gauge) but it has a dual element of a Europiccola, and a pressurestat from a pavoni eurobar (think that's the name, the pressure stat looks bigger and it's all brass no plastic) it's wired with a single switch that feeds both the small and large coil, so they are both on til the pressurestat kicks in. Maybe I should try and disconnect the small coil and see if that makes a difference, but I'd imagine it won't since the pressurestat is there to stop the heating process once it gets to the temp it's set for? ( sorry for the rambling think that made sense)
I ordered the stick on thermometer that goes on the group for orphan espresso, will see if that can help with shot consistancy etc...

The bleeding false pressure issue only applies with a closed boiler system with a pstat....the LP Pro vs the two element EuroP for example. If the pressure is monitored by a bleedoff steam valve like on the EuroP machines this bleedoff of steam serves as a one way vacuum breaker and allows the boiler to continue heating. It is only the pstat models that have the false pressure phenomenon so that the pstat kicks off the element when it reads the top setting, even though the water in the boiler is not up to temp.....the pstat responds to the little bubble of pressurized air at the top of the boiler.
Another thing to keep an eye out for on these pressure readings is the accuracy of the gauge on a pstat machine. Since there is no vac breaker on the machine the cooldown cycle when you turn the machine off creates a vacuum inside the machine which pulls the gauge needle hard against the zero stop pin, over and over day after day and eventually the gauge willl not read a true zero at the pin or the actual pressue at the top. This is part of the reason why Olympia went with a pinless gauge on their newer machines after they removed the vac beaker cap from the design.

You can always try brewing before it gets up to temp, monitoring the group with the new stick-on gauge.

I need to order a couple of those when I place my orphan order.

PC

orphanespresso wrote:The bleeding false pressure issue only applies with a closed boiler system with a pstat.... It is only the pstat models that have the false pressure phenomenon so that the pstat kicks off the element when it reads the top setting, even though the water in the boiler is not up to temp.....the pstat responds to the little bubble of pressurized air at the top of the boiler.

OK, I've been experimenting with my Gaggia Factory 106.
This morning, I turned on the machine, and waited or it to get to the top of the p-stat cycle, and and opened the steam wand. it doesn't have the usual huge drop in pressure that I associate with releasing false pressure. On my two-group, when I release false pressure, it goes from 1.1 Bar to about .4 Bar in about five seconds. The Tin Man goes from 1.1 Bar to about .9 Bar in five or seven seconds, and and the heating element kicks on. It will maintain that pressure for as long as I have water in the boiler, too. This morning I let it run for about 25 seconds. I then turned it off, and repeated the process. Same thing.

On another note, I've discovered that I can let the machine warm up, and then turn it off while I prepare the beans and milk. By the time I've ground, dosed and distributed, I'm down around .6 Bar. I'm doing a 10 second 'pre-infusion', a five second pull, and a three second 'Fellini', finishing with another fifteen or so second pull. Remarkable thick, auburn-crema'ed, complex shots! And I have y'all to thank for that!
Thanks!

Psyd:

After getting it down to 0.6 bar, are you turning it back on and letting the pressure rise before pulling the shot, or did you do it while it was off at 0.6 bar?

On my 106, I typically warm it up, and pull 2 blank doubles to warm everything up and then pull my shots. Today I pulled only one blank double before the shot and although the temperature was much lower, the shot was incredible. I need to start playing with these lower temperatures to see if I've been pulling while it's too hot. Just going by taste since I don't have a temperature gauge.

Thanks.

peacecup wrote:Any lower than that and you won't get much milk for steam, and will take a while to get water into the group when you lift the lever.
PC

PC this is a joke, but I like you can get milk from your machine. Did it take you long to learn to milk it?