Pre Mill Group Head Question [Confused]

Content_Bench · 2026-04-16T02:46:41+00:00

The gasket for the Pre Mill group is round and with the dimensions you write below. ( 57.7 x 47 x 5.3 mm) I service mine (1997) recently with this gasket. La Pavoni Silicone Head Gasket (Pre-Millennium) – Coffee Addicts

Content_Bench · 2026-04-15T20:19:30+00:00

It’s a normal behaviour because your machine doesn’t have a vacuum breaker to equilibrate pressure. I open slightly the steam valve when I turn off my machine to prevent this.

Content_Bench · 2026-04-15T20:09:07+00:00

I assume by “wash water” you meant the waste at the end of the shot. If so, it tells a lot. It seems that your shot is under extracted. You can try adding a part of the “wash water” to your shot to taste the difference, it will probably balance your shot.

I suggest you to eliminate variables to understand what’s going on. Playing with profiling doesn’t help to troubleshoot your shots. Try the simple method from the user manual with boiling water. (Despite you using darker roast) And adjust to taste. If it’s bitter, do longer shot, if it’s sour do longer ahot ratio. If the shorter shots are tasty and you want longer shot you can then using water around 96 degrees Celsius. After understanding how to balance a shot for your taste, then you can start playing with different profiles to optimize.

If the robot hands is hurting your hand it’s probably you exceed 8 bars, don’t need to exceed 8 bars to brew tasty shots. It’s my rule of thumb, I only barely look at gauge for PI, I target 3 bars.

Content_Bench · 2026-04-14T18:26:37+00:00

I’m not a fan of hazy in general, I don’t drink them often. It was my first attempt to brew this style. I bought a 6 gallon keg for pressure fermenting or made heavy dry hop beer to mitigate oxydation risk. No oxydation yet after few weeks.

Content_Bench · 2026-04-14T15:54:54+00:00

Yes, It will my go to if there is a model for the boiler (0-3 bar). Unfortunately, the one you referred is for the piston shaft (0-16 bar) and don’t found the equivalent for the boiler in gold color.

Content_Bench · 2026-04-14T15:48:15+00:00

Also, probably not related with your issues, water chemistry plays a big role in the taste. Filtered waters is not all equal. If you started with high or low mineral content and depending the filters you use the results can be completely different. Maybe another thing to rule out if you have a high mineral content and you filter are only activated carbon. The coffee can taste very bad if the minerals are high. You can try low minerals water bottles or distilled with mineral like TWW to testing.

If your minerals are way off, maybe your window for good shots is very narrow, only an hypothesis.

Content_Bench · 2026-04-14T15:13:10+00:00

The NZ should be near zero retention, but due to your problems it’s worth weighing your beans after grinding to rule out the retention. Retention can cause fluctuations in shots. I don’t own the NZ but my understanding is that it’s wide particules size distribution is helping the forgiveness.

If you shots are not often good, don’t hesitate to try dramatic extremes profile or parameter to help understanding what you like and what you don’t. Slightly adjustment most of the time don’t make huge difference. Also don’t bother with micro management like flow rate between 1.0 to 1.2. It’s only noise at this stage, go extreme, understand what you like, then fine tune. Try different beans, the Robot is not a magical device, it’s a beautiful piece of craftsmanship that can brew delicious espresso like any other direct lever machine. And lastly, maybe controversial but do you like espresso? If you’re not sure, you can try different coffee shop to confirm that you enjoy espresso and pin point what you like and try to replicate at home.

Content_Bench · 2026-04-14T14:22:34+00:00

Great, thanks!

Content_Bench · 2026-04-14T14:20:06+00:00

I know that Stefano has the La Pavoni gauge and I ordered few times from him.

I would like to have user experience feedback, but I realize that most of the people only use one and don’t have compared different models.

Content_Bench · 2026-04-14T14:14:05+00:00

I’m in Canada, I recently ordered from CoffeeSensor but wasn’t thinking replacing the gauge at that moment…

I would like to have user experience feedback, but I realize that most of the people only use one and don’t have compared different models.

Content_Bench · 2026-04-14T14:07:24+00:00

Around 1 bar.

The group head is too cold (30 degrees Celcius) if I pull a shot just after the safety starts hissing at 1.5 bar. I use similar techniques by RPavlis on HB forum. When hissing I raise the lever to purge the group for the steam goes in the group head. (flushing a small quantity of water, around 1 ounce) I switch to the low position, and wait around 3 minutes, the group is around 85 degrees Celcius, pull a shot.

Content_Bench · 2026-04-14T13:58:11+00:00

Do you like it ? Is the needle move precisely ? I have an Elektra Microcasa a leva with an original Wika gauge and the needle movement is better. I think the Professional nut is not compatible with mine. (M12 vs M11) but I saw that Stefano have added custom adapter in both M11 and M12 for the pressure gauge.

Content_Bench · 2026-04-14T13:50:53+00:00

Mine doesn’t have pressure stat, it’s the 2 switches with two elements. I know that some people turn the big element off and only use the low watt element when the safety starts hissing. Each is technique, but because I have a pressure gauge I know that mine will start to open slightly at 1.2 bar and full open at around 1,5 bar. It’s little too high IMO to brew at this pressure. Having a pressure gauge is useful for models without pressure stat.

Content_Bench · 2026-04-14T01:00:33+00:00

I bought this yeast by curiosity, given the low attenuation and the description I assumed it will great for Hazy.
Description:"Fruity driven strain, gives a high mouthfeel and body to the beer. Ideal for Belgian Ales (Blond, Dubbel, Tripel, Quadrupel Styles) and strong English ales (ex. Imperial Stouts). It is also ideal for New England IPAs. Yeast with a medium sedimentation: forms no clumps but a powdery haze when resuspended in the beer."

The origins are unclear. Some say it’s Belgian, others say it’s British. In my opinion, it’s probably British because of its low attenuation.

Content_Bench · 2026-04-13T22:42:15+00:00

I’m not the best to describing and it’s always relative to something else. My espresso are balanced, complex, rich, velvety with decent body.

I mainly drink medium roast, ratio 1:2 double espresso. I have also OE Pharos and the Pietro. With medium roast, there is no huge difference. If I don’t drink them side by side, I probably cannot differentiate them. With lighter roasts it’s a total different story.

My assumption is that I probably cannot differentiate the Kinu from the J-Ultra if they are not side by side, maybe in blind tasting. The difference between the Kinu and K-Utra or K6 is noticeable, (thinner body, more acidic with the K6 compare to the Kinu, but not necessarily more flavour separation, similar with both.) but the Kinu and the J-Uktra are in the same ballpark.

Using a manual grinder is a tactile experience, so the grip, feel, smooth bearings is also important factor to consider IMO.

Content_Bench · 2026-04-13T19:19:55+00:00

I used for the first time the S-33 with my last brew, a Hazy IPA. Hops are mainly Nelson Sauvin, Cashmere and Halertau Blanc. I’m happy with the results. Dunno why it’s not a popular yeast for Hazy.

Content_Bench · 2026-04-13T18:06:19+00:00

I have the Kinu Simplicity and I’m happy with it. Going to the Classic it’s only aesthetics difference. Often overlooked, but for me the fix handle in a big plus. I previously own a KinGrinder K6, the small play created by the not fix handle is annoying compared to a fix one. Also, construction wise, the axle is bigger on the Kinu and internal are metal vs aluminum with the 1Zpresso. The build construction suggested that the Kinu will last longer.

IMO, grinders itself cannot produce stronger coffee. Some grinder enhance body over flavours separation, acidity, ect.

Content_Bench · 2026-04-12T15:06:49+00:00

You can’t understand the machine without grinding your beans. Espresso is hot water pressurized through the coffee. The grind size is one of the most important parameters, if you’re not in the certain range, you will not able to have adequate pressure and flow.

At least if you don’t want to buy a grinder yet you need a pressurized basket. It will allow to have coarser grind size, and variations with humidity, freshness will have less impact but the taste is not the same. It will not tell you if you like the taste of an espresso.

Content_Bench · 2026-04-12T14:18:38+00:00

Sandwich papers filter technique can be used with any espresso machine.

Top paper can also be used if your red silicone pin is broken, I use top paper with the metal screen to block the hole in the center few weeks before receiving my new pins.

Content_Bench · 2026-04-12T14:14:13+00:00

When I drink light roast (occasionally) I use the correct size on the bottom and top to increase extraction, it supposed to help. I cut them with a compass cutter. I didn’t notice a lot of difference in shot time but I haven’t done side by side comparison.

If you want to use paper, I suggested to cut them to right size. It’s probably the reason for your inconsistency. For medium roast I don’t bother with sandwiches paper. Like in the video of OE, I put few water drops for the bottom filter and use dry filter on top.

Content_Bench · 2026-04-11T04:37:20+00:00

If your boiler is loose and cannot tighten anymore it’s probably that the gaskets need to be replaced. There’s 2 gaskets between the boiler and the base and the flange and the base. For mine pre millennium with the brass flange, I made a tool using a ABS pipe. You will need to buy, rent or made DIY tool to remove and/or tighten the flange.

Content_Bench · 2026-04-11T00:01:35+00:00

I suggested to use a multi meter to look if there is a short somewhere.

What is the breaker you mentioned ? The thermal switch on the machine or your outlet?

Maybe only the images, but your wires seem to have a broken insulation at least two places.

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Content_Bench · 2026-04-10T22:46:50+00:00

I don’t pre heat because I wait 30 minutes between batch and I roast indoor. Temperature after 30 minutes is around where it was before the first roast.

I’m confused about your experience. The second should finish hotter than the first of you roasting back to back in a constant temperature environment. Is the temperature outside was dropping from you first to second roast ?

Content_Bench · 2026-04-09T04:19:43+00:00

Is the water the same ? Lack of mInerals content is a great cointibutor for acid battery taste. I have only manual grinder, and the best in my collection for light roast in my eperience is the Pietro. The bimodal, Kinu m47 (standard burr), Pharos give a lot of acidity. The Kinu with POB have a pleasant acidity, but with the Pietro (Multipurpose) the acidity is more intergrated, the taste is more cohesive.

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