Unavoidable channeling with new blend?

[DaveC]

Reading your post wasn't sure if the machine had a 3 way valve or not, watching the video, looks like it doesn't. This does mean it's easier to get a wet puck, but should be no problem getting dry pucks...I hav done it with an Isomac Supergiada, which also has no 3 way valve.

Watched the Video, about 40-45 second to extract 1oz from what looked like a double basket?

If so this is a little long and also low on volume. For a double basket aim for 2oz in around 25 secs, for a single basket about 1 oz in 25 secs. So whichever your using, you look to be grinding too fine. This also makes it real hard for the excess water to drain from the PF after the shot ends and why you get the dribbling and probably minor sneezes when you undo the PF (especially if you do it quickly).

I think trying a coarser grind will help a lot.

Here is a video of a "just passable" extraction using a single basket and 1oz extracted for comparison if it's of any help.



Dave

[Marshall]

First of all I want to say how awesome the HB forums are! I've learned quite a lot from just browsing around and reading over the last few months. So, thanks.

Indeed, it does look like you've learned quite a lot from the tinkerers here, but mostly the wrong things. Fine tuning a machine is great fun and can help take you from, say, 90% of what the beans are capable of to maybe 95%. But, first you have to develop the skills to get to 90%. One of those skills is recognizing that every blend and every roast is different and that even the same roast will behave differently, depending on humidity, age and the phases of the moon.

If your usual grind doesn't work on a new blend (assuming it is fresh), put the meters aside and focus on adjusting the grind until it at least looks right. Then work on distribution and tamp. When you like what you're getting, that is the time to play with your bells and whistles, and see if you can make it great.

Oh, and Andy S is the creator of Frankensilvia.

[oofnik]

Reading your post wasn't sure if the machine had a 3 way valve or not, watching the video, looks like it doesn't. This does mean it's easier to get a wet puck, but should be no problem getting dry pucks...I hav done it with an Isomac Supergiada, which also has no 3 way valve.

You're right, the machine does not have a 3-way valve. I wonder why it's so rare that I get dry pucks.. perhaps there is some other factor that affects this other than the dose, tamp & grind? I've played with all three quite a lot, and even good shots had wet pucks in the end. Hm.

Watched the Video, about 40-45 second to extract 1oz from what looked like a double basket?

The extraction was actually 31 seconds from the time the pump was turned on. I stopped it when I noticed the flow going blond. In retrospect it should probably have been stopped a little earlier, but the camera messed with my timing. And yes, it is a double basket.

If so this is a little long and also low on volume. For a double basket aim for 2oz in around 25 secs, for a single basket about 1 oz in 25 secs. So whichever your using, you look to be grinding too fine. This also makes it real hard for the excess water to drain from the PF after the shot ends and why you get the dribbling and probably minor sneezes when you undo the PF (especially if you do it quickly).

I think trying a coarser grind will help a lot.

I tried changing the dose down from my usual 17 grams or so all the way down to 14 but the puck still hits the shower screen. I know the shot volume should be closer to 2oz, and I've made the grind much coarser than I've ever had to for any other blend. That is why I'm hesitant to adjust it even farther; I think there is something else that is off here. And just for good measure, I remeasured my tamp on a scale and it's right on.

[another_jim]

I've tried reading the original post, but kept getting lost in all the seemingly irrelevent excursions.

I always pull freshly roasted coffee, but most people don't. Basically, it's gassy, blondes quickly, and has a huge amount of too bubbly crema. The best technique is to grind extra fine and go for ultra-ristrettos. The looks aren't great, but the aroma more than compensates.

[cannonfodder]

First off, don't worry about how the puck looks when you remove the portafilter. Not having a 3-way valve will cause that soupy mess. When you unlock the PF and allow the pressure to vent out like that, the puck gets blown all to pieces. In my bench work on the Gaggia Achille I get similar results. To check for proper headspace try this little trick. Grind/dose/tamp as you normally would. Take a penny (assuming you are in the USA) and place it on the surface of the puck in the center. Now lock your PF in, and then remove it. If the penny is now pushed down into the puck, you do not have enough headspace and need to down dose. Once again, this is a general guideline. Different machines prefer different headspace but this is a good starting point.

On your video, you had several large dead spots on the basket. When the espresso starts to flow, it should flow evenly across the entire surface of the basket. Dead spots are a tell-tell sign of bad distribution. Your grinder is capable, however the Caribou coffee could leave a bit to be desired. Most chain coffees tend to be past their prime.

The grind will change not only from blend to blend, but batch to batch and hour to hour in some cases. Humidity plays a big role in espresso IMHO. Some days I change the grind for nearly every shot.

As Marshall points out, the machine is the smallest factor in the process. While some machines perform better than others, a skilled Barista can make the most of whatever they are using. The largest delta in the formula is on the handle side of the portafilter. It takes time to learn but you are moving in the right direction.

Personally, I would recommend keeping away from Caribou (unless their roaster is local and coffee roaster in the past 3 days) and revisit your distribution method.

You have probably seen them, but if not you may want to look at the Videos of espresso extractions and Tamp and Dose Techniques Digest

[oofnik]

Thanks for the helpful hints Cannonfodder. I'll try the penny method before my morning shot tomorrow.
As far as the video, yes I know the distribution was not very good. Normally however I do get a pretty even flow. I believe it's mostly because of the very low dose I used, about 14 grams - it was about 3mm from the rim of the basket before tamping. I couldn't really even it out with my finger. But regardless, it still expanded and pushed up to the showerhead bolt during the shot. I'm thinking that's bad.

The video was actually of SM Liquid Amber, roasted 5 days prior to about FC+. The roast came out uneven, as evidenced by the bean pic. Maybe that threw things off, I don't know. But as far as the Caribou coffee, I've got a hook up at the store. They get their coffee in 5lb bags and they actually have the roast date on them. My friend tries to get me a 1/2 lb every now and then when the new shipments come in and it's usually 5 - 10 days after the printed date.

Anyway I just ordered 1 lb. of Black Cat. Should be in sometime this week, so by pulling shots with some professionally roasted stuff I'll be able to tell if my roasting is out of whack.

Marshall, I realize that the gauges and meters are not all that there is to making great espresso. I am by no means an expert when it comes to the user variables, but over the last several months I like to think that I have at least improved a little bit. Also, I'm fairly certain that going from a thermostat-controlled, pressure-unregulated machine with a temperature hysterisis of 30 deg. C to what I've got now would make it a little easier to control the user variables without worrying about what the machine is doing. I see it as having less to worry about so I can focus on the things I need to focus on. Wouldn't you agree?

[Marshall]

Marshall, I realize that the gauges and meters are not all that there is to making great espresso. I am by no means an expert when it comes to the user variables, but over the last several months I like to think that I have at least improved a little bit. Also, I'm fairly certain that going from a thermostat-controlled, pressure-unregulated machine with a temperature hysterisis of 30 deg. C to what I've got now would make it a little easier to control the user variables without worrying about what the machine is doing. I see it as having less to worry about so I can focus on the things I need to focus on. Wouldn't you agree?

My concern was your focus on equipment. There is a tendency on these forums to blame the equipment whenever something goes wrong and look for a mechanical or electronic solution. I think that's fine (or at least less problematic) for someone who really knows their way around espresso. I think it's a major distraction for anyone who is first getting into it.

[cannonfodder]

But regardless, it still expanded and pushed up to the showerhead bolt during the shot. I'm thinking that's bad.

But how do you know it is doing that? Without a 3-way, what you are seeing may be a side effect of the puck blowing up when you loosen the portafilter to depressurize. Under normal circumstances, a very light impression of the shower screen/screw is normal.


After the shot

[oofnik]

But how do you know it is doing that? Without a 3-way, what you are seeing may be a side effect of the puck blowing up when you loosen the portafilter to depressurize. Under normal circumstances, a very light impression of the shower screen/screw is normal.

Even if I wait a few minutes for all the pressure to release, I'm still left with a mess.

Anyway my pound of Black Cat came in today, and I truly, honestly have run out of ideas. There is a limit to how many grind settings, how many tamp pressures or distribution techniques I can try before I have to stop for fear of caffeine overdose. Today I reached that limit, and my shots did not improve one stinking bit. I'm really kind of frustrated and clueless right now. The way I understand it is that there are two components of making good espresso: there's the scientific, quantized side, where you have brew temperatures, tamp force, pressure, dose, preinfusion time, etc. On the other side you have the 'zen' part, as I like to call it, which is itself a combination of experience and a level of intuition shared by artists, chefs, musicians, and people who are generally very good at that sort of thing. Both contribute to making excellent espresso. As someone who has been fascinated by science my entire life, I'm afraid I've leaned a little too far to the quantization of espresso and haven't given enough time and practice on my zen. Either that, or I'm just cursed and there's absolutely nothing I can do about it.

What really irks me however is that I used to get shots looking like

, using the built-in grinder (similar in quality to a Solis Maestro), before the pressure mod, before the PID, before I roasted my beans, before I even knew what the WDT was. And now that I have all this stuff that's supposed to help me make better coffee, all I get is crazy channeling armed with an arsenal of spewing jets every time despite a consistent distribution technique, a good solid tamp, and a $270 grinder. It really makes me think.. maybe espresso just isn't for me.
And the worst part is, I keep trying to justify it by making the excuse that my machine isn't good enough and I need to plunk down $700 on something better. Maybe my tamper is at fault? Maybe my filter basket isn't the proper shape? Maybe my group head isn't allowing the correct preinfusion? Or or... But I know it's just me. Only problem is, after eight months of this, all I've done is gotten worse. Unless someone can convince me to keep trying I'm probably going to either go insane or put the equipment up for good. Today sucked.

[HB]

Whew! I just re-read this thread and can relate to what you're saying. I've had days like this, usually right after an equipment change. If it lasts too long, I take a break. But before you do, let's review the problem at hand:

The pressure mod, however, has changed the behavior of the machine quite a lot, and I'm at a loss trying to figure out what's going on here.

And now that I have all this stuff that's supposed to help me make better coffee, all I get is crazy channeling armed with an arsenal of spewing jets every time despite a consistent distribution technique, a good solid tamp, and a $270 grinder. It really makes me think.. maybe espresso just isn't for me.

My first thought reading your last entry was "crazy channeling with no obvious barista technique failures = pressure is too high." That's how I created this beauty:


System meltdown from
Perfecting the Naked Extraction

But you presumably have that angle well covered with a gauge showing realtime brewhead pressure (?). If you have a pressure gauge off a tee near the pump, also check it at the grouphead with a pressure portafilter. And just for kicks, try dropping the pressure to six bar. That should be equivalent to a "chip shot" in golf in terms of extraction difficulty. The crema production and body will drop, but you should at least have a reasonably drinkable espresso, which you clearly deserve.

Other ideas are welcome...

[oofnik]

Ergh.. thanks, Dan. If you check the pic I posted up there of the regulator you can see the tee near the pump going to the pressure gauge like you guessed. Unfortunately I don't have the means to test the pressure at the grouphead, but I don't see how it would differ from the pressure at the pump since it is a closed system with (presumably) uniform pressure. If I had a portafilter with a pressure gauge perhaps I could check it.
I'll try to adjust my relief valve to 6 bar tomorrow and see what happens.

How much of a difference do different manufacturers' filter baskets make? The one I'm using came stock with the machine, and it holds about 17 grams of coffee with a level dose. That's a little larger than the 14 - 16 I've read all over the place for the commercial ones. Perhaps I should try to get a commercial filter basket (and a commercial portafilter while I'm at it) to see if maybe the distance between the holes on the bottom of the basket makes a difference? Just throwing out random ideas I've been thinking.

I've even gone so far as to examine the ground coffee that comes out of my grinder with a jeweler's loop, trying to get an idea of how uniform the grind really is. But since I have no reference, that was pretty useless. I'd give anything for a few hours with a Macap M4 or something, La Cimbali M32, and a few pounds of fresh beans just to see if there's actually something fundamentally wrong with my technique or if my equipment really is to blame. Hm.

I've had days where I could feel the zen. You know what I mean. It's those days where you are just in tune with all the variables and everything is perfect. Today was the opposite.

[HB]

How much of a difference do different manufacturers' filter baskets make? ...I've even gone so far as to examine the ground coffee that comes out of my grinder with a jeweler's loop, trying to get an idea of how uniform the grind really is.

Have you ever seen Karate Kid? You need a half-day of wax on, wax off.

Sorry about that, trying to introduce a little levity into an otherwise grave situation. I share Marshall's concern that you're trapped in analysis paralysis, looking for demons where none exist. Filter baskets do make a slight difference, but are not responsible for a shift from beauty shots you brag about to "crazy channeling." If you're weighing the coffee for the sake of consistency and doing the WDT, it's reasonable to expect you'll have a drinkable shot in three tries for just about any blend, assuming you've got the basics down, which there's every indication you do.

So what's up? Possibilities include:

• You've acquired a bad habit that you very consistently reproduce. The only one that comes to mind is incorrectly dosing; some machines really don't like overdosing, for example. Some will channel if the dosage is too small. If you've got the thickness of a nickel on lock in, you're good for almost every machine out there.
• The pressure is wildly off. If the flow rate is correct, in theory you can't go too far astray with a vibe pump. The max pressure is inversely proportional to the flow rate, so unless the shot is near stalling, it can't go much over 10 bar. I suggested a large drop in pressure to drop your frustration factor. It's easier to pull a good extraction at 8 bar versus 10 bar.
• Something is up with the grinder. I add this only because you mentioned it's a new piece of equipment. The new guy always get blamed.

And of course we could chalk it up to espresso gremlins. I've had them a couple times, and always around the time that I changed something (grinder, espresso machine, blend). Once or twice I've bought coffees that I simply could not get a decent shot from. When that happens, I go back to a known standard and recalibrate. A few months later I might retry the troublesome one, only to find it's a wonderful coffee. Roasters blame that on "stinky beans" or some such...

[oofnik]

How about this. When I get the chance, I'm going to film my entire espresso ritual from start to finish, post it on here, and you tell me if you see something absurdly wrong with what I'm doing.
Oh, and about the pressure, well I guess unless my pressure gauge is wildly uncalibrated there's no way the pressure could be off. Usually it goes like this. Pump starts, gauge reads 0. After about 2 seconds it pops up to about 6 bar for 2 - 3 seconds until I see coffee, then hovers around 8 bar for the first 6 - 8 seconds of the extraction, then the relief valve cracks, which is set to about 9.5 bar when it reaches about 9 bar. Sounds about right to me. But whatever. I'll sleep on it and hopefully come up with an idea for tomorrow. Thanks a lot so far.

[jesawdy]

I've been told (in an espresso class, no less), that the definition of insanity is doing the exact same thing over and over again and to expect different results. I was tryng to froth milk on a 5-hole LM Linea steam wand.... my experience is a one-holed Silvia. The instructor might have been referring to me...

I would dial that OPV down to like 8 bar if you don't want to go so far as 6.... then like 7 or 6. If I wanted to get real drastic, I might unplumb that whole thing and go back to stock just to see... but I am crazy.

[cannonfodder]

Here is a video I did for the Achille review from grind to finish

[oofnik]

I've been told (in an espresso class, no less), that the definition of insanity is doing the exact same thing over and over again and to expect different results.

Oh man, I've done that on more than one occasion. At least I know I'm insane though
Well, today was a little better. I pulled some halfway decent shots with less jets. I tried dosing a little more (+.3g), and I concentrated all my zen into making my tamp level, which was a problem I've been having since my perpendicular sense is pretty horrible. And also since my tamper sticks out a 1/2 inch from the top of the PF when it's fully compacted instead of being flush it's really hard to tell whether I'm level or not. I'm going to cut it down one of these days on the lathe.
Anyway I've had a cold and a stuffy nose for the past few days, so my sense of taste is not quite right, so I'm probably just going to take a break for a little while until I can taste the nuances of flavor again. Thanks all for the help so far.

edit: Thanks a lot for the video, cannonfodder. I really can't think of anything I'm doing that's not in line with what I've read for the last several months and what you did in the video, so I'll just have to wait until the gremlins go away and pull some more shots.

[HB]

The wax on, wax off saga continues...

I concentrated all my zen into making my tamp level, which was a problem I've been having since my perpendicular sense is pretty horrible. And also since my tamper sticks out a 1/2 inch from the top of the PF when it's fully compacted instead of being flush it's really hard to tell whether I'm level or not.

Try removing the portafilter's basket retainer clip and tamp the basket on the countertop. Before lifting out the tamper, give the basket a quick twirl and it will be really obvious if the tamp is canted (unfortunately too late to fix it). It's also a good habit to run your finger along the basket's edge before lifting out the tamper to feel if the tamper is unlevel.

[erics]

Personally, I think you have diagnosed your own problem in your original post.

I, for one, believe good espresso is a synergistic combination of lots of factors and even "minor" factors within the major catagories. The EXTENT to which each contribute to that ever elusive "godshot" can be debated ad infinitum.

See this: http://www.coffeeresearch.org/espresso/definitions.htm

I can't think of any downside to installing a PID vice the original click-style thermostat other than $. All you're doing is dramatically improving something the mfg had on the machine in the first place. Installing an OPV on a machine that, for whatever reason(s), didn't have one COULD BE questionable. There are ways to accomplish the same thing that an OPV accomplishes - some I am familar with - others not. At least one high end machine (Salvatore) has been reported to be without an OPV and certainly the majority of all lower end espresso machines lack this device.

It seems to me that everything started going downhill when you installed the "pressure mod" - so why not simply reverse that mod and start from there? When I look at your "pressure mod", I see lots and lots of teflon tape around those threads and some of that tape may have ended up in places it shouldn't.

Eric S.

[oofnik]

Try removing the portafilter's basket retainer clip and tamp the basket on the countertop. Before lifting out the tamper, give the basket a quick twirl and it will be really obvious if the tamp is canted.

Yep, it's pretty consistently unlevel. Tried it a few times. I knew it would be, since the tamper sticks out of the basket so much that it's virtually impossible to get it to be level. I'll need to chuck it in the lathe and shave it down about 3/8" so it will be flush with the rim of the basket. The few tamps that I did manage to get level produced consistently better shots, just as I expected.

And Eric, that's a good point you brought up about the teflon. After I installed everything however I ran about two tanks full of water though the machine to make sure it was thoroughly flushed out, then disassembled the boiler again to make doubly sure there was no build up of anything I didn't want in there. So I'm about 99% sure that the teflon isn't a problem. I'm going to go recharge my ion exchanger (haha, that sounds so sci-fi) in a bit and see if that will help too.
About the pressure, removing the mod would really be more trouble than it's worth at this point. Instead, I tried to adjust the relief valve so that it wouldn't open at all during the shot so the machine would behave like it did before the installation. I think the problem with trying to decide whether or not the mod helped or hurted is that my technique is still not consistent enough to evaluate the machine's performance accurately. I think that that's biggest problem I'm having here, and I'm trying to blame it on the machine, when it's really just me.

I don't think there is a way to improve my technique consistency other than practice. So it'll take a few more pounds of beans until I can really decide. All I was trying to do with the mods was to make my machine do what it should have been doing in the first place, and do it consistently. As I've said before, now that I know what my temperature and pressure are, and that they are consistent, I can concentrate on improving my skills with less distraction. It's a never-ending journey, but it's fun, and that's what counts.

[erics]

Assuming this is your machine,

http://www.partsguru.com/LaPavoni...itanaEspresso.html

take a look at parts MC112, MC112/1, and MC028. If I remember correctly, the water to the shower screen (and yours IS pristine?) flows through this check valve on the outside threading of part number MC028. Just throwing out some numbers here, the pump discharge pressure (as indicated by your pressure mod gage) may very well be 9.0 bar, but the pressure the puck is really seeing is a lot less than that because the threading of MC028 is acting, in essence, as an orifice.

So now, when you crank the regulating valve stem out (CCW) until it is loose, there should be zero flow in the flex line from the regulating valve back to the tank during a shot, i.e. the entire pump output is directed towards the puck. Your pressure gage may very well be in 12-13 bar territory. So now, assuming there are no teflon tape tidbits in/around MC028, you should be "back in business."

The above, of course, is how I read the design of the machine, i.e. it was never intended to have an OPV. BTW, removing MC028 typically requires a special precise wide blade screwdriver blade so, while you're cranking up that lathe . . .

I think it should be obvious that, in this particular case, I believe the problem lies in the machine side of the portafilter.

Good Luck,

Eric S.