Is the Cimbali new or used, and is it old? Does it pull good shots on other machines?

I've had a few experiences with consistent, major meltdowns, and in my experience they are actually pretty rarely the result of barista error. One cause is very high pressure. I know I said 11-12 bars is OK, and it is for a short while (ramp up to it and back off quickly), but it is terrible for a flat-line profile. It will ruin every single shot you pull no matter what-even if you manage to get them to look right they will taste awful. If you want to make your machine easier to use, lower the pressure. If you go too low you'll lose a lot of body, though, which is why you'll likely want to keep it over 8 bars.

Another major cause for consistent meltdown is the grinder. If your burrs are old and dull, or have been dulled by a foreign object like a rock passing through them, you may see lots of spritzing and drama, and your shots will certainly taste bad even if you don't see that. If your burr carrier is misaligned, you will see all the same, except new burrs won't fix the problem.

Make sure you get the idea of a specially sized tamper making a big difference out of your head. Seriously. I've never heard such nonsense in my whole life! People all over this forum have been getting great shots from VST baskets without 58.3mm tampers. Thinking that this is going to save your shots is the kind of magical thinking that will impede your progress, IMO. I'm not saying that a tamper can't help. Maybe it can. I doubt it, but if it's the case the amount it helps is fractional at the very best: not the kind of thing that will turn your shots around.

Lastly, I'm no fan of Red Bird coffee myself, but last time I tried it, it seemed like the kind of coffee that shouldn't be pulled 3 days off roast. I don't recall if I tried it with a VST basket or not, but I would certainly also try it with a more 'traditional' basket as well; I've had a lot of more traditional espressos (dark/medium roast, low-acidity flavor profile) that don't work so well with the VST basket and shine by comparison on a Synesso double basket.

I had a hunch that the VST tamper wasn't necessary, so I'm glad I decided not to buy it. Someone had suggested to me I would need it, so I'm glad you helped to dispel the myth. What's your favorite standard non-VST basket? I used to love my ridgeless double and triple baskets on my Silvia, but I received those baskets from a friend and they are in storage. Not sure where he got them from or even what they are. LM maybe? I'd like to get some standard baskets to play around with.

Warrior (Mike) thought the grinder had about 70 pounds of coffee through this burr set, but he doesn't use this grinder anymore. We were operating it with the top off....gears and burrs exposed...at first the worm gear wouldn't allow it to grind fine enough, so he manually forced it down into the finer range. I think the grinder could be the culprit. Dunno yet. Another friend of mine is going to let me borrow his Mazzer Mini E for a couple days, so I'll get another crack at this starting tomorrow. Will report back then.

What's your favorite standard non-VST basket?

These baskets are a bargain - especially when you buy six or more: http://www.espressoparts.com/EPMZ_107A? ... id=1651956 .

And, BTW, , the one reason to shut the water supply off before making some initial adjustment to the pump's relief/regulating valve is that "ya never can tell what's gonna happen" when you start loosening & tightening various machine components.

I am very happy to report my previous issues with uncentered extractions must have had everything to do with the Cimbali grinder we were using. John Roos, who owns Roos Roast in Ann Arbor, generously let me borrow his Mazzer Mini E for a couple days and already my pours are very centered with the VST baskets and the Shot Brewer. I had a series of hilarious squirters with week-old Black Cat (not sure why....maybe temp was too high), but I switched beans and baskets and went back to centered pours.

I am not yet drinking mind-blowing espresso, but I think that has everything to do with beans. Just goes to show it really is primarily about the coffee you use. Can't wait to get my hands on a bag of Blue Bottle Roman Espresso since I have a lot of experience with it on three other machines (and at low temps gets incredibly sweet with great body).

Eric - Hadn't seen those baskets before. The holes on those baskets are arranged in a funky octagonal pattern. Espresso Parts advised me that they are just as good as the LM version of the ridgeless baskets....but they are back-ordered on the LM versions (might not get them back in). So I may go for these HQ octagon pattern baskets or I saw Stefano's still has the LM versions in stock. Nonetheless, the VST baskets now seem to be performing fine.

Got a chance to log some temperature data. The first one is using the WBC method detailed here:
WBC Procedure for Measurement of Brewing Water Temperature
and can be compared to the GS3 and Linea data here:
La Marzocco GS3 Thermal Performance Quantified



The next one is a real-world-walk-up-to-it-and-pull-several-shots-3-minutes-apart chart

Thanks for the graphs, Shawn. Shot Brewer's consistency is looking pretty good. I think this rising intrashot temperature profile is similar to a GS/3.

Here's a brief video of the sensitivity of the manual paddle, and this should apply to the Strada MP and the few hybrid GS/3s popping up with this group design. I taped a calligraphy tip to the paddle so you can see the range of sensitivity. I think of this paddle as having 4 positions: off -- something like 3 bars -- something like 6 bars -- 9 bars (full pressure). There are probably more, but this is workable for me. In the middle of the paddle, there is about a 1 mm range that goes from 3 bars to 6 bars (marked with a white sticker in the video). But, I usually need to overshoot whatever target pressure to the left a smidge and then back off to the right to get it to maintain the target. So, if I want 3 bars, I move the calligraphy tip to the left side of that white sticker initiating the pressure ramp, and then back off to the right side of the sticker. This usually begins the flow of the espresso. Move back to the left side of the sticker, and this will hit about 6 bars. I use the rest of the range for swinging the pressure up to 9 bars, but if you fidgeted back and forth some more, you could find some pressures in between. It's demonstrated here with a backflush disk inserted.

So far, I barely use the pre-infusion, and I prefer immediately swinging the paddle to full pressure. Lots to learn about pre-infusion's effects in the cup, but the immediate 9 bar extraction is producing the kinds of textures along the lines of what I was hoping for.

Thanks for posting the video, Jon. That clarifies a lot.

Just a little fun with the Shot Brewer, Versalab, and my morning brew of Verve's Santa Ana Guatemalan. This single origin from Verve honestly tastes like cherry cola. Get some! Thanks to erics for the tip on the HQ ridgeless baskets. They are great and inexpensive.

erics wrote:Borrowing one of Shawn's pics -

This is how you do it . . . with the water supply to the machine SHUT OFF, slightly loosen lock nut (2), turn adjustment screw (1) about 1/4 turn counterclockwise and retighten lock nut only finger tight. Open water supply and brew into a blind basket, adjusting pressure to your desired value.



Now hold adjustment screw stationary and gently snug up locknut past fingertight - maybe 1/12 of a turn. Recheck pressures with the machine fully warmed up and while brewing a typical shot.

BUT . . . something seems amiss . . . your pressures should not have varied like that. You should be feeding this machine with a pressure regulated water supply of ABOUT 2.5 bar (~35 psi). It has a balanced bypass valve on the pump that is designed to accommodate varying inlet pressures but 35 psi seems very reasonable.

I have recently adjusted the OPV down to 8.5 bar on this machine. Now I am seeing that it is dumping much more water into the drip tray than before.

I think I understand this, but just to be sure... doing the adjustment that erics describes here will reduce the flow from the pump and reduce the excess water dumping from the OPV, right? But I shouldn't expect the actual brew pressure to drop unless I over-adjust and bring the pump down to below 8.5bar, correct?

I have recently adjusted the OPV down to 8.5 bar on this machine.

There are two adjustments for "brew" pressure on this machine. The "OPV" in this case is a thermal overpressure valve designed to relieve the brew boiler when pressures exceed 11-12 bar - let's call it 11.5 bar. This pressure is created when the brew boiler water gets heated in an idle machine and the incompressible water has nowhere to go. The OPV you adjusted should now be adjusted to go drip . . drip . . drip when the pump pressure is 11.5 bar - and this is how you do it:

In your particular case, turn the adjustment on the valve 1/6 turn clockwise and brew with a blind basket. Now adjust the PUMP's relief/regulating valve such that the pump/brew boiler pressure is 11.5 bar. With 11.5 bar the thermal OPV should be doing a drip . . drip . . drip.

Now readjust the pump to your desired brew pressure - 9.0 bar with a blind basket should produce nice results under real brew conditions.