"Vibiemme Domobar Double" Review
6-19-2011 (updated 12-5-2013)
by Randy Glass - Copyright 2011-2013 - All rights reserved


      There are espresso machines and then there are espresso machines. They can be had for the price of a nice shirt, or they can be had for the price of a nice car. You can write a love note with a Bic pen as well as with a Waterman fountain pen. From Timex to Rolex. Wherever your point of view points.. as it were.. there are choices. On July 15 the UPS gentleman delivered a large, heavy parcel. Large.... heavy... Did I mention heavy?
      Unless you are younger and larger than I, you too would pull out the hand truck to get the 84 pound parcel into the house. Yes, the Vibiemme Double Domobar (which we affectionately call "DeeDee") from 1st-Line has arrived. If you have not been paying attention to the espresso machine market, this machine caused quite a stir when it first arrived on the scene in its first iteration. This, the third generation, has seen a lot of hands-on changes and updating of design and build, driven in a great part by Jim at 1st-Line and Stefano Stefano's Espresso Care. I cannot comment on the previous generations but will detail this newest offering from Vibiemme, and will try to do some compare-and-contrast commentary with my Vibiemme Domobar Super manual (lever).

FEATURES
The Double Domo is a very sophisticated machine. Some of its features include:

  • Dual boilers. The 1.9 liter steam and hot water boiler, and the .5 liter dedicated brew boiler.
  • Thermosyphon heating of the group using the brew boiler's full capacity (no heat exchanger).
  • The brew water's feed line passes through the steam boiler to preheat the water. This limits the thermal effect of what would have been cold water entering the much-smaller brew boiler during extraction. This preheat pipe only runs through the water in the bottom of the steam boiler and not through the steam.
  • A proprietary control system that cycles the heating elements. They operate at various times so that the steam and brew boilers can be kept ready even on a standard home 15 amp circuit. This is yet another feature that helps limit temperature drift in the brew boiler.
  • PID controlled brew boiler with pre-programmed offset so that the display temperature matches as closely as possible to the actual brewing temperature.
  • The steam boiler is regulated by a pressurestat while the PID operates through an SSR to control the brew boiler.
  • Rotary pump only (no vibratory option).
  • The user can choose whether to use the reservoir or to plumb the machine directly to a water source. A lever-operated valve on the bottom of the machine allows easy switching from one water source to the other without opening the machine. If the user plumbs the machine, descaling is an easy matter by using the reservoir and just switching the valve to that source.
  • The drip tray can be "plumbed" to an external waste system or it can be sealed and used as you would a "regular" drip tray. Sealing plug is included.
  • Frame, case, and drip tray all in stainless steel.

          I am not the young man I ever was, and it was a lift of Olympic proportions to get the machine up on the cart. I think it weighs in at about 65 or 70 pounds empty which isn't all that terrible, but lifrting it up from the floor before the feet are attached is a dead lift that begs one to get assistance (or better knees). OK... so I'm nearly 60 years old. There. I said it.

    ANATOMY LESSON
          Let's take a brief look inside and see how they did it:


    RIGHT SIDE VIEW
    1 - Brew Boiler
    2 - Motor for Rotary Pump
    3 - Support for "Black Box" (behind this bracket)
    4 - Return Line for Group Thermosyphon
    5 - SSR for PID control of Brew Boiler Heating Element

     

    LEFT SIDE VIEW
    A - Steam Boiler
    B - Fluid-O-Tech Rotary Pump
    C - Jaegar Pressurestat
    D - Vacuum Breaker Valve
    E - Pressure Relief Valve

    SET UP
          Getting it out, up, and running involves first removing the machine's box from the outer shipping box. I then placed the machine's box on it side and slid DeeDee out onto the carpeted floor (this is starting to sound like an R-Rated movie script). Once removed from its packing, setup includes:

  • In some cases it is necessary to removing the stainless outer cover of the machine and pulling out of an "Instapak" (a water-activated foam packing). I believe the Instapak is to hold the rotary pump and motor as well as the brew boiler in place to protect them from movement and damage from casued by rough handling during shipment. One the outside of the inner box, right over the taped opening, there is a warning to remove the Instapak internal protection. 1st-Line is looking for an alternative shipping method to avoid the rough handling so common these days with the major shippers. Once that happens the warning label will not be included.
  • Hooking up the external water source (if so desired)
  • Either hooking up the drain line or removing the drain fitting and bolting in the drip tray plug (included).

          As you probably have read here on my website, I installed a water softening system a few months ago and so the line was ready to hook up to the machine. DD comes with a long, stainless-braid supply line. One end is pipe threaded to connect to an elbow on the bottom of the machine, pointing towards the rear. The other end now has a female BSPP (British Parallel Pipe) thread so you need to get either a proper adapter or use a USPP fitting and lots of teflon tape to get it connected. I get about 30 pounds of pressure through the 3/8" John Guest supply line at the machine, so I opted to not use a pressure regulator.
          If the user chooses to plumb the machine, the reservoir's low-water shutdown switch must be defeated. That is easily accomplished by tightening the screw in the center of the reservoir's platform. Simply tighten the screw to pull the tray down until you hear the microswitch click indicating that the circuit is closed. If you switch back to reservoir use (such as when descaling) it is important to reactivate the low-water shutdown switch by removing the screw so that the pump is protected from running out of water.
          Also included is a long, wire-reinforced vinyl drain hose. It slips over a single-barb fitting which protrudes through the bottom of the machine. The fitting can be angled to either side, and then the nut securing the connector to the machine is tightened at the bottom of the face, behind where the drip tray slides into place. I used a nylon tie wrap (not included) to be sure the hose was secured to the fitting, and ran the drain line behind my coffee cart and through a hole I drilled in the cart's backside. The hose's end drops into a three gallon water bottle in the cart's lower section.


    The drip tray has a fitting that "plugs" into the drain fitting on the machine if the user chooses to plumb a waste line. If not, the fitting on the tray is removed and an included plug installed through the hole.

          During the setup, the removal of the Instapak was a bit of a challenge. I found that I had to reach in, crush a portion of it, pull it out as best I could, and repeat that crush-and-pull cycle three of four times before I could remove it completely. It can help to open the gray outer bag and pull out some of the foam out as you go, working carefully.
          Removing the Instapak evidently pulled the ribbon cable off of the PID's control/display module as well as pulling it free from the control black box. I discovered this when I powered the machine up and the display did not power up. The PID evidently still operates with the cable off, but there is no way to see the temperature to verify that.
          Hooking up the display side is easy because there is a locator cut-out that matches the protrusion on the cable's connector. But there is no physical indication on the black box. The wiring-diagram sticker on the black box showed where position "1" was on the box (like on the old IDE ribbon cables), and I aligned the red stripe of the ribbon cable in that direction. Of course, where a 50/50 chance was offered I picked the wrong one. I contacted Jim, and as always, 1st-Line came through with the information I needed. I had to remove the outer case again and reverse the cable's connection at the control box. From then on it was smooth sailing. All new owners are well advised to carefully check for disconnected wires, cables, insulators, and anything else that may be inadvertantly dislodged during the removal of the Instapak.

    IMPROVEMENTS
          For those who followed along with my trials and tribulations during my use of the Vibiemme Domobar Super will understand my relief over various changes made from that machine (from four years ago) to this one:
    - The DD's entire machine's frame and body are all stainless steel, so I can hopefully forget about any significant rust problems.


    - The drip tray's right and left edges overlap the sides of the machine as seen above. Additionally, an extended lip on the face of the machine greatly limits the possibility of water getting under the drip tray.


    - The vacuum relief valve on the steam boiler (seen above) as well as the main pressure relief valve are both plumbed into the drip tray so the inside of the machine is protected from excessive moisture problems (this feature protecting the internal electronics and wiring should be standard on all machines!).This becomes even more important becasue the pressure relief valve for the brew boiler also serves as an expansion valve. Since the brew path, including the brew boiler, contains no airspace, as the increasing pressure of the water in the brew boiler has to be vented. The relief valve is set at around 12 BAR.
          I was quite happy to see channeling of the water and steam into the drip tray after recently reading a report of the failure of a $500+ control box on a La Marzocco GS3 (a $6500 machine) because of water inside the case getting into the electronics. The pressure safety valve on the steam boiler is not plumbed into the drip tray. A cup and drain tube would be a nice addition here. Normally, this valve only opens under extreme conditions such as pressurestat failure. And unlike the LM problem, the electronics are located high in DeeDee's case so even in the case of a catastrophic leak the electronics should be fine, even if your carpeting isn't.
          With all the plumbing draining into the drip tray there is no return line in the reservoir. For those who choose to use the reservoir as the water supply, no hot water will re-enter the reservoir. For those who do plumb to the water main supply, the reservoir will never have to be removed or emptied. A damp, forgotten, unused reservoir in a hot environment would get nasty in a hurry. In other words, all waste and bypass water goes to the drip tray. I actually removed the reservoir and pulled the intake filter from the reservoir's hose from the machine to protect the plastic reservoir from heat and to eliminate a possible cause of vibratory sounds.

    ROTARY PUMP
          For those accustomed to a vibratory pump, a rotary pump (a Fluid-O-Tech in this case) is a different animal. The pump has an incorporated bypass that is pre-set (but adjustable) for the desired brew pressure. The large, brass pressure relief valve, as found in the DS, is only there as a safety device and to act as an expansion valve for the brew boiler, and it is set to open at well above the normal brew pressure. Even with a blind filter inserted to backflush, the pump's own bypass regulates the maximum pressure and the pressure relief valve does not open.
          Another benefit of a plumbed rotary pump machine is that the pump is always supplied with pressurized water from the water source's supply line. There is no valve that controls this flow of water through the pump, through the boiler, and to the group. That path is always supplied with pressurized water, and that means when you open the brew valve water will pass through the group even if the machine is unplugged from the mains electricity. It makes it difficult to accidentally leave the lever in the open position, but it also give you a pre-infusion function. Pull the E-61's lever up to its mid-position and water flows into the portafilter. Count some number of seconds and then pull the lever all the way to the brew position for extraction to begin.

    SIZE AND APPEARANCE
          Familiar features from the DS would include the utilitarian design which has carried through the Domobar line. If you want something pretty, flashy, or to match the wallpaper, look elsewhere. The smooth, flat surfaces of DD are easy to keep clean and the huge E-61 group is a sculpture in and of itself, and that is all just fine with me. The E-61 group is the same as used on the DS models including the two socket-head bolts to remove the top nut for mushroom access. The manual group is the only one available on DeeDee. I like simple machines, and for me, there is sufficient electronic complications in this machine so there is no need to add more just to save the trouble of raising a lever and watching the stream or the second hand of a clock.
          The size of the DD compared to the DS shows that externally they are identical (using a tape measure). The exception being that the drip tray overlapping the edges of the frame which adds about 1/4 inch to the width, so your spouse is going to have to find another reason for you to not upgrade. When you consider the fact that, compared to the DS, the DD adds a second boiler as well as replacing the much smaller vibratory pump with a rotary pump and its motor, it is quite a design feat. Of course, something has to give. The reservoir is smaller in the DD and there is less open space inside in which to work if repairs are needed.

    LET'S POWER THIS BEAST UP!
          It didn't take but a few minutes of getting the machine operating to become addicted to having it plumbed, both at input and drain. What a joy it is to not have to worry about whether the reservoir is sufficiently filled for the next pull or how wet my shoes will be when I try to carry an over-filled drip tray into the kitchen. If your machine has ever shut off in the middle of an extraction because you forgot to fill the reservoir, or your slippers permanently smell like coffee from a spilled drip tray, you know what I am talking about.
          The user can choose to have just the brew boiler on (power switch position I), or to have both boilers in operation (Switch position II). You can also place the machine in switch position II and turn the PID off which leaves only the steam boiler on. Handy for making hot soup, poaching eggs, or steaming open letters. I left the machine in Position II for about six hours on the first day and can say that the top panel becomes a very effective cup warmer. Even the buttons for the PID on the front of the machine get quite warm. While not too hot to press, they can become uncomfortable to hold for more than a few seconds.
          After allowing it to sit at idle for the first couple of hours I used the hot water function to force the steam boiler through numerous fill cycles. The water as well as the steam had that "new espresso machine" smell to them, but that completely cleared away after the flushing. I did the same with the brew boiler.
          Among the first day's impressions was that the power of the steam from this thing in impressive. It really pumps out a prodigious amount of steam and it seems drier than the steam from the Domobar Super which is a HX machine. I can only guess that the level of the water is further from the steam exit pipe from the DD's boiler and so the flow of steam brings with it less moisture.
          On the afternoon of that first day I used the DD to pull two doubles. I flushed a bit of water but didn't get that flash of steam or near-boiling water as I did from the DS. The Kony was unchanged and I used the same coffee beans I used with the DS this morning. The grind was too fine. At first I got a very slow, thick, over-extracted start to the extraction, and then the puck must have fractured and the rest was a watery brew. I loosened the grind up about three "steps" (lines on the Mazzer's setting wheel) and the next pull, while slightly over-extracted, was drinkable straight. A good start! I steamed enough milk for one cappuccino and after opening the valve about 3/8's of a turn I had to turn the steam down to keep the milk in the jug! Interestingly enough, after a few mnth's of use I find that I must have have become more accustomed to DD as I am grinding at just about the same setting I was with the DS.
          Because the brew boiler is plumbed directly to the group (no heat exchanger) as well as being quite a bit smaller in volume than the DS's boiler, DeeDee seems to come up to brewing temperature faster than the DS did.
          When you adopt a new machine there is going to be a learning curve. It takes time to learn its idiosyncrasies and then to tune the machine as well as your process to get the espresso adjusted to your taste. After four years with the DS, that describes where I am. Vibratory to rotary. Pour over to plumbed. HX to double boiler. It is only day three with the machine but things are settling in. One of the changes in my habit is to make use of the inherent pre-infusion that is available with a plumbed rotary machine. The Vibratory pump on the DS slowly ramped up the pressure and so had a sort of built-in preinfusion as the pump built pressure to open the valve in the E-61 group, but it was not user controllable.
          Does pre-infusion make a difference? On the second morning I pulled the lever all the way to brew (no pre-infusion) on the first double (old dogs, new tricks), but remembered and pre-infused the second. I didn't tell Val and had her sample the two cappuccini I made, and she could tell the difference, liking the pre-infused cup better. The taste of the second was smoother and sweeter.
          On day three, I am trying to learn DeeDee's temperature idiosyncrasies. I had transferred my group thermometer (Eric's) from the DS to DeeDee. On this morning I watched the thermometer, and was impressed as to how long during the extraction the thermometer read 203.5 F. I will try to document some of my findings, comparing and contrasting the PID's display to the brew temperature as well as the flush amount needed compared to the DS. For now, I have the PID set at 203 and my goal is just to try and get accustomed to how the machine behaves.
          The PID has a pre-programmed offset of 19 degrees F. The offset is to attempt to have the PID's display to show the actual brew temperature at the group instead of the boiler's temperature. There is heat loss as the water flows from the boiler, through the various pipes, and to the coffee. Because of that a PID is set to a temperature above the brew temperature. The temperature drop will vary depending on the ambient air temperature as well as how long the machine has been left on so the user has to adjust the PID's set temperature to taste, the offset gives a more realistic reading in regards to the actual brew temperature on the display.
          The cooling flush which is so critically important on the DS could use quite a bit of water, particularly if the machine has been sitting at idle for an extended length of time. There were some occasions when the DS's group thermometer read around 210-212 when flushing. DeeDee never gets that hot even after being left on for long periods.

    LE CRITIQUES DU OBSERVATION´
          As with earlier models, there is a lot of metal-to-metal contact. The outer case cover is screwed directly to the framework. No big thing as this is very common in the industry, but the large size of the cover makes it difficult to form the machine without having created some spacing between the cover and the framework in some areas and that creates vibration-noise points. The cup warmer/top cover is the same. There is one small, thin strip of rubber at the back edge of the warming tray, but the addition of such isolation strips on various other parts of the machine would be welcome. Don't misinterpret these comments. The rotary pump helps make this machine's sound quieter and smoother than the DS's vibratory system, but there is room for improvement.
          I found it a bit odd that the reservoir does not have a cover. It is fully open on top unlike the DS's reservoir which was enclosed and had a plug for the filler opening. Not a problem for me as I do not have any intention of using the reservoir, but just in case, a cover would have been a nice touch.
          Until the US switches to BSPP thread (which is planned for a week after never), and European espresso machines continue come with BSPP pipe thread on their plumbing lines, it would be nice to include the proper size adapter.
          Do I need to mention the waste of injection molded plastic that is the included tamper? Probably not. If it were at least the correct size, that would be great. It isn't. This machine deserves a quality tamper anyway, so, Vibiemme, save the plastic to make model car and plane kits.
          The center of the drip tray's plumbed exit is about ˝" up on the backside of the tray and so the tray holds some water after it has drained. A drop-in molded plastic filler of some sort that funnels the water to the drain would be nice.

    EARLY CONCLUSION
          After a few months of use I will update this review (or add a "Part II") to document impressions after the excitement of early-ownership wears off and when I have accumulated some data to share. Much like a hook-up in a bar, things look great at first through beer goggles, but in the light of day on the next morning things can change. Some time in September or October I will report how DeeDee looks "in the morning." Early impressions do point to good things, though.
          For now, one of the questions would concern the cost. At a current price of $2650 shipped, the law of diminished return is certainly being enforced. But the sort of person who holds espresso quality on this high of a pedestal is not going to judge any machine on a dollar:espresso-quality ratio. When you compare DeeDee to a $1500 espresso machine, you are never going to get twice the quality of espresso by spending $3000.
          In the case of DeeDee (literally and figuratively), you get a lot of research and development, not only by Vibiemme but also by the US importer, their agents, and their customers. A number of the complaints and concerns I had with the DS have been addressed and resolved in the DD. Beyond that, the machine has undergone extensive testing and has achieved a level of temperature stability and control that was virtually unheard of in a home machine just five years ago (more or less).
          So for now, only you and your bank account can decide if DeeDee is your kind of girl. But the feature set and temperature control alone should certainly put her on the short list for anyone looking to spend this kind of money on an espresso machine. Check out further details of this machine at either 1st-Line or from Stefano's Espresso Care.


    OBSERVATIONS AFTER 2˝ MONTHS OF USE - 9/23/2011
          It's been a full three months since DD arrived here and I continue to be impressed with the espresso. The consistency that the dedicated brew boiler delivers is remarkable. After the first few day's dialing in I do not think I have made a bad espresso. My wife often asks, "Did you change something? This tastes different," when I switch blends as she can easily taste the difference in her morning cappuccino when I change something. Day after day the DD pulls excellent shots
          There are a lot reasons for the consistency and excellent results I have been having. The preheating of the brew water before it enters the brew boiler, the entire brew boiler's contents used to thermosyphon-heat the group, the PID controlled brew temperature, and the outstanding and massive E-61 group. Those all work together to bring temperature controlled brewing water to the coffee. The temperature throughout the extraction as indicated on Eric's group thermometer varies no more than about two degrees Fahrenheit through the extraction, and compensating for the thermometer reading about two degrees high, the brew water is usually just plus or minus one degree from the PID setting. The Vibiemme E-61 group has an excellent dispersion pattern and the socket-head bolts make it very easy to disassemble for occasional lubing or cleaning chores.
          I cannot leave out the fact that the combination of plumbing the machine along with the manual E-61 lever group has given me preinfusion and the ability to control it. I preinfuse every extraction until the first drops appear on the screen and have gotten some extractions that are closer to three ounces before the viscosity becomes watery. These longer extractions in a cappa are really quite nice.
          The bottom line is that if you have a DD and are not getting great espresso, there is a problem, and odds are it isn't the machine. if you need some help in that department, I have just today finished and delivered the new owners manual specifically written for the VBM DD to Stefano and Jim, so it should be posted soon on their websites. Even if you don't plan on getting the machine, check it out as it contains quite a bit of educational value in general.
          I can't say whether this machine is better than "Brand X." I am not in a position where I can compare the DD to its competition. I can comment on its performance compared to the machines I have owned. Silvia? She is a novice trying to compete in the major league in comparison. it's not even close. Compared to the Vibiemme Domobar Super, the DD is far more consistent, and most likely for the differentiating reasons listed above, the DD delivers a better balanced, smoother cup delivering more of the nuance tastes we love about espresso. Being that the DD is over $800 more expensive than the DS we would certainly hope so! The new rotary DS is just $650 less (did I really say that?), and for the difference I think the DD is worth the investment. There is more going on here than a shiny case. If you are the kind of person who makes long term investments in this sort of gear, seriously consider this machine.
          As I write this on Friday, September 23, 2011, it is just two days away from a birthday - On September 25, 1961, fifty years ago, Carlo Ernesto Valente filed the U.S. patent 3,230,974 for "Alternately Seating Valves" which we now know as the E-61 group. If you have not read the patent, and particularly if you own an E-61 machine, you can download a copy of the original patent HERE.
          So Happy 50th E-61, happy espresso to me, and thank you, Ernesto Valente, for your great invention. I sure do love the espresso from this machine!
    OBSERVATIONS AFTER 4 MONTHS OF USE - 11/19/2011
          After four months of use some benefits of this machine have become clear. It is not a stretch of the cognitive thinking process that the greatest benefit of this machine's design is the PID-controlled, dedicated brew boiler. Along with the excellent design of this machine, it offers remarkable consistency. Putting that to work in your benefit doesn't take much once you get the hang of it. Here is hat I have been doing to take advantage of the control this machine offers:
          I allow the machine to warm up for about 30 to 40 minutes in the morning. I allow the machine to warm up for thirty to forty-five minutes each morning. After prep is completed and I am ready to begin pulling shots, using Eric's group thermometer I flush until the temperature first peaks and then drops 0.5 degrees. After that I grind, dose, tamp, manual preinfuse, and pull.
          That had been working really well, but at some point, dare I say "suddenly," the quality of the espresso fell off. Around that same time I switched suppliers of green as my regular source had fewer available origins available. I chased a few variables, but could not figure out what it was. Some information from Eric led me to raise the boiler temperature. I had thought that the differential between the thermometer and the brew temperature was two or three degrees, but Eric informed me that it was closer to 5 or 5.5 degrees. As much wiser men have previously stated, "BINGO!" That did it.
          I offer this, not so much to present more fodder for those bent on mocking but to point out how easy it is to modify and control brew temperature parameters with this machine. We can debate whether it was the change in green coffee or some other factor that necessitated the change, but the ability to change is the point to note.
          The balanced flavors I am getting have been a delight. Some wonderful citrus acidity along with deeper, richer notes that linger on the palate.

    OBSERVATIONS AFTER 5 MONTHS OF USE - 12/22/2011
          After 6˝ years with a SBDU machine, then a few years with an HX machine, it takes some time to tweak ones head to the correct attitude for using an espresso machine that is so dependably-repeatable and consistent in its function as well as giving precise adjustment. I roasted some coffee from a new supplier and found it a bit harsh. I dropped the temperature on the brew boiler's PID and everything fell into place. Delicious espresso. Eric's group thermometer verified that the brew temperature was, indeed, one degree cooler (a "rounded-off" one degree). SPeaking of Eric's group thermometer, I find that to do a cooling flush for the DD after it has been at idle for some time, remove the portafilter, lift the lever, and watch teh temperature display. It will rise, peak, and as soon as it drops .5 of a degree, stop the flush and then grind. dose, tamp, lock and load, and pull the shot. This has been working for me quite well. Thanks Eric!

    OBSERVATIONS AFTER 2˝ YEARS OF USE - 12/5/2013
          I rounded-up the total time by one month, but yes, it really has been two and one half years since my Vibiemme Double Domobar arrived. A recent post on Coffeegeek.com prompted me to open up DD and do a cursory inspection. I had been planning to do it for a while, but needed this little push. The original poster related some concern about his new DD and some of the internal wires near or on hot parts, so with screwdriver in hand I went to work.
          Once I had access I removed the steam boilers level probe to inspect it for scale buildup and to have a visual look into the steam boiler. No photos of the heating element, but using a strong LED flashlight I could see that there was just a very thin patina of mineral build up through which I could still see the gray of the element's outer surface, so no worries there. Keep in mind that I have never done a descale on this machine. I credit the use of the Chris Coffee water softening system for keeping scale at bay. I also regularly check the system's function with the Aquarium Pharmaceuticals GH+KH test kit.
          Here is the boiler's water level probe after being removed and allowed to dry


          As you can see, it too is showing a very thin patina of scale. I polished this with Bar Keeper's Fgriend and it removed all the scale present and left a smooth, shiny surface. I will probably check it again in three years or so.
          The only notable problem I found inside was that the aluminum tape that holds the white wool (fiberglass?) insulation on the steam boiler has come loose:

          Current machines have their boilers insulated with a rubber (silicone?) mat which I would eventually like to get and use to recover my boilers.
          The only change I have made since the previous update to this review is a modification to the drip tray screen. To eliminate, or at least lessen the splashing which occurs when the 3-way valve opens, I opened a hole in the screen under the group's lower extension as seen here:

          It took a Dremel with a small bit to cut through and then clean the hole's edges so that there would be no burrs or sharp areas which might catch a cleaning rag... or skin.
          Other than that, it's just been day after day of very nice coffee.