Hi all,

I would appreciate some of your expertise as to the problem I'm currently experiencing with my Gaggia Carezza. The problem is the increasing pressure(?) or water volume(?) that increases as the shot goes on. It seems to be generally independent of dose, anything from a 15-20 gram dose and the only thing that changes is the initial pour speed. The video is pretty classic for the issue I've been having. The distribution and tamp seem to be right on as the initial bit of espresso coming through seems to be very evenly dispersed. However, as the shot goes on, the cone gets bigger and more blonde. The result is a lot of not-very-thick crema on top of a lower volume shot than I'd like.

Another possibly unrelated thing the machine has been doing is pausing the water dispersion for 1-2 seconds when I run a basic water flush through after the machine has been warming up. Usually the longer I let it warm up, the longer the pause is. It initially releases some water for maybe 1 second, stops for 1-2 seconds, and then starts back up without stopping until I flip the switch again.

The machine is totally stock, w/o any modifications and I'm grinding with a Le'Lit PL53 that gives a fantastic, clump free grind.

Thanks for any help!

How's the espresso taste?

To answer the taste question, it's not terrible, but it certainly isn't as robust as I'd like it to be. There is definitely good espresso flavor (using SM's Monkey blend) but it lacks the kick that I have become accustomed to, especially when made into a latte or americano.

Now that the video is up, I'll say you can really notice the big cone at between 23-26 seconds. Sorry for the poor lighting and such, this was an impromptu recording

Thanks again!

Looks like there's some channeling going on in the middle of the shot, and that's what's making your cone get so big. You might want to try WDT and Stockfleth's for dummies to see if that helps.

As for the pause in the water flow, my Gaggia Coffee at work does the same thing when I pull a flush before the shot. Usually the water starts out bubbling and boiling because it's too hot, then it tapers off to nothing, then it comes back and pours more normally. I think it's because the boiler is small, the thermostat lets the machine run a bit hot, and perhaps the boiler's not full when you first turn it on. It doesn't seem to hurt anything, though, so I don't worry about it. The main thing is to flush the boiling water before pulling the shot, or the shot will be very bitter.

I don't recall my Carezza pausing the water stream... but I used to run water through the steam wand at the beginning of every session. Since the steam line connects to the top of the boiler, water from the steam wand means the boiler is full to the top. I would recommend doing that to get the best performance from your small boiler.

Interesting. I know I've had channeling problems before, but those usually go off to one side or another. I know this shot wasn't particularly perfect by any means, but it seems like if I get an uneven tamp it is usually immediately obvious in the way the first few drops come through. I do already perform the WDT and I feel I get a very even distribution in my portafilter. In fact, I have performed my technique on my brother's Quickmill Alexia and gotten a good, no-big-coner shot out of it.

I've heard of problems with the pressure on these Carezza's being set too high (with the unfortunately non-adjustable OPV valve) from the factory. Maybe this has something to do with it?

Thanks again!

smarch wrote: I've heard of problems with the pressure on these Carezza's being set too high (with the unfortunately non-adjustable OPV valve) from the factory. Maybe this has something to do with it?

YES. When your pump gets all quiet and the first drops start to squeeze out,,, you are likely pushing over 12 bar with that unregulated vibe pump. (The lower the flow, higher the pressure.) A calibrated OPV for 9 bar will really help you with that kind of shot. The grind and dose will be much different for 9 bar vs. 12+ to get the same flow.

@Frost. Thanks for the comment. I knew these things have OPV problems but I couldn't decide exactly how this would affect my shot (more flow or less). For clarification purposes, are you saying the pressure being set too high is what may be causing the high flow problems at the end of the shot? Sort of like the pressure getting way too high at the beginning and blowing apart my puck? If that's the case, I may have to look into that mod.

Look at the vibe pump pressure/flow graph in the post below:

The importance of brew pressure, purpose of adjusting OPV?


These Gaggias (at least the no 3-way valve variety) have an OPV that only functions as safety overpressure, they do not open at brew pressures , they do not open if you stall the pump. So on the pump/pressure graph, WYSIWYG. An OPV that can be adjusted to 9 bar brew pressure will tend to flatten that volume/pressure curve as you get to the lower flow rates.

Your basket will not have to be loaded like a fortress to resist the extra pressure. The grind more coarse and the extraction will be different under a lower and more stable pressure.

I have similar problems with my 3-year-old Gaggia Classic. When the machine was new every pour was too fast, even if I ground the beans almost at the point where the grinder burrs were touching. I then discovered that the Classic has a variable OPV, and based on advice I found online (CoffeeGeek, as I recall), I found the time-and-pressure curve for the pump in my unit and reduced the pressure from 11 bars to 9.5. Results are better now, and occasionally excellent, but a typical shot for me will take 6-8 sec to start pouring, will drip for a few seconds (I don't have a bottomless portafilter), flow in tiny threads, barely holding together, for a few seconds, and then the flow will accelerate until the shot generally blondes by 25 sec tops. Crema is almost always a light, cappuccino brown. Since we use good, freshly roasted coffee and we have a good grinder (Macap M4), the results are better than any coffee shop or restaurant that I can access easily (except the Intelligentsia Cafe on Jackson Blvd in Chicago, where they seem to produce God shots like General Mills produces Cheerios); however, my periodic espressos at Intelligentsia, using the same Black Cat beans that are our staple, show me that I am leaving a lot of complexity and nuance in the portafilter.

Would welcome any thoughts on solving the "accelerating pour" problem.

Jeff