Help with Quickmill Alexia extractions?

[Sam]

So, to start out with, the basics: I'm running a Quickmill Alexia at 8.5-9 bars of pressure, fresh beans from Barrington Coffee, a Macap M4 doserless grinder, bottomless PF with a a ridgeless triple basket and one of two tampers (convex and flat).

I moved up to the Alexia a few months ago from a Silvia and Rocky combination. Lately, I've been having realllly frustrating problems with extractions on her. I grind, dose into the PF with a yogurt cup, stir up the grounds, brush to even out the pile, tamp, lock in, and pull the shot. Lately, the puck has had some weird characteristics. There seems to be a shallow crater in the dead center (or, sometimes, just a channeling hole) unless I dose up enough that the only discernible pattern on the puck is the showerscreen.

When I knock out the puck, it comes out in two pieces: a curved mound comes out, and the negative of that is left in the PF. It looks like the sides of what's left in the PF are dark and extracted, while the center is lighter and looks underextracted and dry-ish. What would cause such an uneven extraction through the puck's center? I've used both a flat and curved tamper, varied tamping pressure, etc.

The shots have also started to blond early and don't have a really dark, rich crema that I'm able to get at the shop down the street (pulling the same beans on a Cyncra... which, obviously, is a tad fancier). Help... please.

[jesawdy]

Do you have a bottomless portafilter? Other than the early blonding (and comparisons to a Cyncra!), are the shots suffering in taste? Coffee age?

Also, are you thermostat or PID controlled?

The Alexia seems to need a warming flush or two from idle to warm up the group. I am also seeing the highest temps intrashot (after prior warming flushes) for a pull just after or about 10-20 seconds after the heater light goes out. For a very slightly higher temp, pull another short warming flush after the heater light goes out. With my thermostat setting (unchanged from arrival) this results in a ~199-200F shot.

The coffee I used this AM on an Alexia was quite long in the tooth.... I tried 15g and it was a blond gusher. I dialed down the grinder and dosed 16g, better but still a tad fast, I still drank it. (I need some new beans!)

With only a week under my belt on Alexia, I've been finding 16-17 grams has been treating me pretty well.

[Sam]

I'm using a bottomless PF, and seem to have at least avoided blond gushing. I'm also not getting the insanely thick pour cones I've seen on some bottomless portafilters, but i don't know if those are good or bad. The shots are lacking the sweetness I came to expect from this coffee (pulled from the Cyncra). I'm mostly concerned by how light the crema is (in color, not thickness). I pre-warm my cups by pulling blank shots into them, letting the element turn on, and when it turns off, dumping the water from the cup and pulling the shot. I got used to doing that with my Silvia (minus the temp surfing). At that point, the shot is a little too hot to drink. I don't know if I'm off on my temp or if i'm overheating the cup (seems impossible). The cafe I go to just has their cups sitting on top of the cyncra, and I'm always surprised at how lukewarm the actual cup is. Still, their coffee kicks butt (Amherst Coffee if you're anywhere near western Mass.)

The coffee is never more than a week old. As for warming - it usually warms up for about 30 minutes, then I pull two or three sessions (pulling a shot until the element light comes on) to get everything hot enough. At that point, most everything seems to temperature.

[jesawdy]

On the crema color, the temp may be too low. Or the shot ran long and overextracted. You could try updosing and/or grinding finer.

On the sweetness of the shot, that's going to vary with dose, grind and temperature. If you're friendly with the shop that has the Cyncra, perhaps you can get some particulars on their variables? If they are somewhat typical of the current trend in the higher-grade shops, they might be pulling closer to triple ristretto territory and nowhere near a normale.

[Sam]

They only pull triple ristrettos. I went in and talked to one of the baristas about the problem, and he said they were finding that double baskets tended to fix the problem I was having, but they didn't. They pull at 9 bars - I'd ask what their temp is, but I have the dial, not the PID, so I'm not sure how close I could realistically get. Thanks for your help!

Oh - I love the article, but the Alexia seems to require much more headspace than what's in those photos. If I dose to that level, I'll screw the screen into the puck, so I try to keep it down. I'll try raising to 10 bars and see what happens - I'll also play with the temp to see if that's causing any of the problems.

[HB]

When I knock out the puck, it comes out in two pieces: a curved mound comes out, and the negative of that is left in the PF. It looks like the sides of what's left in the PF are dark and extracted, while the center is lighter and looks underextracted and dry-ish. What would cause such an uneven extraction through the puck's center?

It could be transversal or donut-shaped side channeling. Are you updosing? Have you checked the puck clearance? Is the dispersion screen clean and the water jet breaker operational? My suspicion is that the center is denser and providing more resistance; if you're updosing, this would be exacerbated by dispersion screen compression. I wonder if Ken's demonstration of even preinfusion would confirm:


From How to Preinfuse; Extraction Pressure Redux

While not the point of Ken/Jim's investigation, would pressurizing for 5-7 seconds and then stopping allow you to confirm the even diffusion of water? If you see a dry core like the above with drippy perimeter, we'll know the cause is an uneven extraction.

Oh - I love the article, but the Alexia seems to require much more headspace than what's in those photos. If I dose to that level, I'll screw the screen into the puck, so I try to keep it down. I'll try raising to 10 bars and see what happens - I'll also play with the temp to see if that's causing any of the problems.

I have been getting good results with a dose of 16-17 grams and brew pressure of 8.5 bars.

[jesawdy]

My 'crummy' beans from this AM performed much better this evening. Dosed 18g (in the 14g LM-style ridgeless basket which may allow more room than the stock baskets, I've yet to try them) and tamped the heck out of it. I've also been under the covers and dialed back the brew pressure from 10bar to about 9.5 bar (so far) and monkeyed with the thermostat every so slightly higher.

The shot was for a cappuccino, so no comment on the espresso taste but it sure looked pretty.

[Soshry]

Hi Sam:

I also own the quickmill Alexia. I don't know if you remember me but you helped me greatly on Coffeegeek when I inquired how to find the OPV valve. I also use the Macap M4 grinder and I am getting good shots so I will try to share my methods with you.

1) I also recommend that you switch to the double basket. when I tried to use the triple basket that came with my naked PF, I was getting a lot of "gushers". I never could get the triple basket to work with the Alexia. Also you may want to try a ridged double basket instead of ridgeless. I'm not sure what difference it makes, its what Chris of Chris Coffee recommends and it seems to work for me.

2) I do not think you need to use the WDT (dosing into a cup and stirring the grinds) with the Macap M4. It is a great grinder and I think it already does a good job at minimizing clumping. I do slightly overdose and then use a wooden barbecue skewer to "chop" the grinds down criss-cross style. I read that somewhere, I am not sure where. I then use the "stockfleck" method to move the overflow to 6 o'clock and 12 o'clock, 3 o'clock, and 9 o'clock and then sweep the excess off the top of the basket. I then do a light (5 lbs) tamp followed by the N,S,E,W nutating tamp. I then lift the PF of the shelf and do a GENTLE rap flowed by the 30 lb tamp (i use the espro clicking 58 mm Flat bottomed tamper) flowed by a 360 degree polish with the same pressure.

This method gives (most of the time) great double extractions. I go to some of the top espresso places in NYC ( 9th street espresso and cafe Grumpy) and I get pretty good results with the Alexia at home using the methods I described above. My machine does run at higher pressure (10-11 bars) I am not sure what difference, if any, this makes.

I think the main thing is to temporarily go to the ridged double basket that came with the machine. This basket is the most forgiving. If this does not help, I would suggest contacting Jason at the Chris Coffee service dept. He is extremely knowledgeable about the Alexia.

Good luck and please let me know how it works out. Thanks again for your help in finding the OPV.

Steve

[Sam]

I've raised the temp on the stock thermostat and underdosed the triple basket to give a lot of headspace - so far, it seems to be helping a lot. I need to run more test shots today to see if it's actually a consistent improvement, but I'm hopeful.

HB: Can you control the pre-infusion on the Alexia?

Soshry: I've tried ridged and ridgeless doubles and triples, and haven't noticed much difference in any one basket. Thanks for the advice, though - I'll see if I can dig up the original double basket and see what happens.

[HB]

Can you control the pre-infusion on the Alexia?

No, that's handled by the E61's "alternating valves" design (patent explanation). The extra headspace reduces the risk of disturbing the puck during lock in and increases the "water cushion" for more even water dispersion across the puck's surface. The trick is to have enough clearance to allow a nice water flow, but not too much. The swelling of the puck should press it against the dispersion screen; the puck's constrained expansion helps avoid channeling (especially along the sides).

[Marshall]

It sounds like you have an unevenly saturated puck.

I've had a Zaffiro (the Alexia's blood brother) for four years and tried all sorts of variations in baskets, loads, tamps, temps and vudu ceremonies. I am pretty well convinced that even or slight underdosing in a real (ridged) LM double basket works best on this machine. If the grounds are well distributed, a light settling tap or two, followed by a couple of leveling sweeps of the finger does the trick. After the settling tap, most of the grounds are below the lip. So, I'm really just evening them out inside the basket, not sweeping them off. A moderate tamp, and then I'm done.

I never did get good results with a triple basket. I also think they waste a lot of coffee, while overdosing you on caffeine.

Oh, yeah. I get more consistent results with a convex tamper. Before that I was using the heel of my hand to form a crater in the grounds.

[Sam]

Thanks for all your help, everyone. Sadly, I'm still getting insanely frustrated by the shots. I have two more symptoms for the shot doctors out there; I know one is relevant, and I'm not sure about the other.

1) If I leave Alexia unattended for, say, five minutes, the pressure reading drops to zero and it takes a good 20 or so seconds from the pump turning on to any water actually appearing. Shots done one right after the other don't have this wait time.


2) No matter what I do, drops start appearing and falling from the naked PF well before the pressure reaches 9 bars (sometimes around 3-5 bars). I can't seem to get that nice buildup and drop pattern that I see on so many shot videos. The shot still blonds early, but the puck shows no real sign of channeling.

I've tamped harder, lighter, convex, flat, overdosed, underdosed, stockfleth, WDT'd, etc.

Are there any Western Mass. folks out there that might be able to see Alexia's trickery in person to help?

[HB]

Hmm-m. Could you post a video? A bottomless pour could be revealing, but a start to finish video of your routine may turn up clues we're not catching based on your text description. See What am I doing wrong? and My attempt - Silvia and Rocky for example videos.

[Sam]

Sadly, all my photo equipment is still only.

Weirdness: I ran a usual backflush, and now the pressure profile is completely different. The needle used to sluggishly move up to 8.5-9 bars, and now it very quickly shoots to 4ish bars for a second or two, hangs out there, and then proceeds to the normal pressure. The flow rate also seems a bit higher. I have no idea what happened.

Is there any way to get into the showerscreen area without doing gasket damage? I don't have a replacement gasket, but I'd be curious to see what's going on up there.

[HB]

Is there any way to get into the showerscreen area without doing gasket damage? I don't have a replacement gasket, but I'd be curious to see what's going on up there.

Sure is, see the FAQs and Favorites under "E61".

[jesawdy]

1) If I leave Alexia unattended for, say, five minutes, the pressure reading drops to zero and it takes a good 20 or so seconds from the pump turning on to any water actually appearing. Shots done one right after the other don't have this wait time.

Sam,

I haven't had anything quite like this happen to me yet. I have come up to the machine on a few occasions and not had immediate water from the group as I started a warmup flush, but never more than a few seconds. Never after only 5 minutes.

While not the Alexia, I did note that Mark Prince had an issue with the Isomac Zaffiro (another single boiler E61). In the Conclusions of his Detailed Review of the Zaffiro, Mark said:

Another minor issue that cropped up in my testing is a fill problem with the machine. Sometimes, when it is left on for 24 hours or more without a shot being pulled, activating the pump doesn't seem to direct water to the brewing group. The fix is easy - run the hot water switch to get water flowing through the steam wand. Once it flows, your brew group is ready to go. I can't figure out why the machine does this, but it's a minor problem for me.

When this happens, you could try cracking open the steam valve and activating the pump switch. If it takes awhile to get any water out the steam wand, I would assume a pocket of air/steam, or something like that.

[Sam]

I poked around the machine some more and found a problem.

Even when the machine is idle and the pump is off, the OPV line is returning water to the tank at a steady pace. This might be why I need to refill the boiler so often and why the pressure profile seems strange. Does that make sense? What can be done about that?


Edit: I called Chris Coffee and they think the whole set of problems might be related to a problem in the OPV valve's seat. I'll take a look at it, and they're sending out a new OPV seat and spring just in case I can't fix the one I have.

[Philg]

Hi,

I'll have to look tonight to be sure but my Alexia seems to work a lot like yours. Pressure is usually at 0 after it's heated up and if I let it sit too long (more than an hour) it often takes a long time ( up to 20 - 40 seconds) before I get water through the group - same with running the pump with the steam wand open, 20 - 40 seconds before anything comes out. The pressure gage goes up pretty evenly, rests at 4 and then up to around 9, it was around 12.5 before I turned it down.

I use the 18g basket (forget what it's called) with around 21 grams of coffee. I had just been leveling with the tamper, I've been trying fluffing up the grounds and leveling before tamping - regardless, I never get close to what I like for texture if I run more than 1/2 an ounce or so - the shots are usually almost all crema and settle with 1/4" or more but the texture & taste isn't good if I try to pour more than a 1/2 oz.

I don't have a lot of experience with good coffee from shops (one good shot from 9th St - thick texture, fuller cup) to compare and my guess is the early blonding / thin texture is my poor technique but I'm very curious to hear what you discover. I'd love, at least, to not have to run the pump so long to get water.

I used to use 23g of coffee and the pucks came out clean, now with fewer grounds, they're sometimes breaking in half but there are other variables - humidity and different beans at least, so I don't know if that's the same as your experience. I'll have to take a look to see if they're dry in side.

Good luck!
Phil

[jesawdy]

I called Chris Coffee and they think the whole set of problems might be related to a problem in the OPV valve's seat. I'll take a look at it, and they're sending out a new OPV seat and spring just in case I can't fix the one I have.

Sam, thanks for the follow up.

Pressure is usually at 0 after it's heated up and if I let it sit too long (more than an hour) it often takes a long time ( up to 20 - 40 seconds) before I get water through the group - same with running the pump with the steam wand open, 20 - 40 seconds before anything comes out. The pressure gage goes up pretty evenly, rests at 4 and then up to around 9, it was around 12.5 before I turned it down.

Sounds like you should follow up on this issue with the vendor. FWIW, I've been pretty happy with most of my 1.5 ounce shots.

I need to keep an eye on the idle boiler pressure on my test machine. I don't think it usually sits at zero, slightly less than 1 bar, IIRC.

[Sam]

I took the OPV apart and the seat wasn't sitting correctly - so there was a pressure bleed that was throwing everything off. It now holds pressure well and ramps up correctly, so hopefully things will get better. I'll run tests this week and report back if the frustration is over. The idle boiler pressure sits around 1 bar, and stays around 4 right after the shot is pulled. This looks like better behavior. Thanks, all!