Pulsating flow on Andreja Premium

[dsc]

Hi everyone,

I'm not sure whether this problem was there when I first got the machine, but recently, for the last 8-10 weeks I've been getting pulsating on all of my shots. It looks like this:



Now on it's own it would be ok, not great, but still if it wouldn't affect the cup, why worry. But of course besides that I also get early blonding which annoys me so much

Here's a short story of what I do and how the whole ritual of grind/distribute/tamp looks like:

- measure 16.8g of coffee beans, which equals around 16.5g in the basket as usually that 0.3g gets stuck somewhere in the grinder

- grind into a double basket using a bbq stick to break any clumps

- distribute using a needle tool, breaking any additional clumps and distributing coffee evenly around the basket

- tamp with a properly sized convex tamper (fits the basket perfectly), usually only one tamp with around 8kg

- lock and load

[during grinding I start the cooling flush which ends around 25-30s before I finish preparing the shot. Usual temperature of extraction is 91*C measured with a sheathed TC via the nut hole on the group]

Machine: QM Andreja Premium
Grinder: Macap MC4 doserless
Beans: 6days old Monmouth espresso blend (fresh roast)

Eric suggested it might be caused by a faulty bleeding valve, so I took it out, cleaned it and put it all back together. The valve works and the problem still exists, so I guess that wasn't it.

Anyone has any idea what's going on?

I know I might be getting side channeling, because once the low water level alarm went off and cut a shot just after 8s, so I was able to see how the puck was dampen. The middle of the puck was dry while the side were darker and wet, so I assumed most water goes around the centre, down the sides of the basket. That was when I was still dosing less than 16g, so I upped the dose to 16.5g, which kind of delayed the point of blonding. Still not enough to make me happy and probably side channeling is still there because when I knock out the puck the sides usually stick to the basket as if they were more wet than the centre. I won't even mention that with lower doses I got massive blonding after only 13-15s, and that's with really fresh coffee.

Cheers,
dsc.

[BobS]

As a long time Andreja owner, it looks more like it may be a couple of issues - the brew pressure is
too high (which will cause the side and center channeling) and that maybe the tamper you're using
is a bit too small for the basket.

But I'm guessing on the above. The video looks like something similar to the uneven flow one would
see on a bottomless portafilter. I'd suggest modifying that portfilter with a hole saw and getting a
good view of what's happening.

What is the brew pressure showing when pulling a shot?

Bob

[Beezer]

My Anita (very similar to the Andreja) likes a dose of around 18 grams. So you might want to increase your dose some more and see if that helps. Also, I've found a convex tamper works better than a flat one. i think that's because of the curved dispersion screen on the E-61 group. If I use a flat tamper, I get channeling a lot more often.

The flow on your shot also looks pretty fast, so you might want to tighten up your grind a bit, until it almost chokes.

[HB]

I know I might be getting side channeling, because once the low water level alarm went off and cut a shot just after 8s, so I was able to see how the puck was dampen. The middle of the puck was dry while the side were darker and wet, so I assumed most water goes around the centre, down the sides of the basket. That was when I was still dosing less than 16g, so I upped the dose to 16.5g, which kind of delayed the point of blonding.

I agree it's channeling, look at the sudden color transition between 14 seconds into the pour (first frame) and 16 seconds into the pour (second frame):





If you had a bottomless portafilter, I bet it would reveal a "donut" extraction - lots of flow at the perimeter, none at the center. In addition to attention to distribution, try grinding a lot finer (about 4 notches on the Mazzer Mini; I think that works out to around 6 full revolutions on the stepless Macap M4) and reducing the dose to 15 grams. The lower dose and finer grind will give the puck more time to expand / close fissures and avoid "corking" the center.

[CafSuperCharged]

Dan beat me to it: this must be channeling. Another remark of him to grind finer and dose less, I would also second.
In my Andreja, with my parameters, it takes a bit longer before the coffee starts pouring out.
The one time you described where the pour was cut off because of the water tank running under level, the center was dry.
I think it was a thread led by Dan that concluded concave tampers cause more density in the puck in the center than the sides and do not push some of the grind to the side.
I think your case proves his point.
If you revert this, you might want to use a flat tamper, or Italian style, dose a gram less than Dan says, grind a bit finer even, just level and there you go (but now you totally depend on the quality of the grind and its distribution in the PF!)

With Andreja, personally, I use a doserless grinder, grind into a glass that perfectly fits the basket, rotate the glass when grinding into it, tamp with a flat tamper, next tamp lightly with a concave tamper. No channeling ever. I would want to improve on the grinder still, one day, as I think extraction could be improved. Also, I operate at the edge of the grinder's adjustability and cannot go fine enough to work Italian style (which is funny as the - small - grinder is Italian and used in bars for the occasional decaf.)
I consistently have warm, dry pucks that could make some in this forum happy, with a small ring of coffee sticking to the wall of the basket that does not come off when knocking.

Regards
Peter
Netherlands
Europe

[dsc]

Hi guys,

thanks for the replies:)

Brew pressure is 9 bar, boiler pressure moves between 0.9-1.1bar. The tamper is perfect for this basket with no space in between the tamper and the basket.

I agree that this is side channeling, although I have tried using various methods of preparation:

- worked with low doses, 14g, 14.5g, 15g, 15.5g
- tried different tamp forces, light tamps, only tamping with the weight of the tamper, hard tamps (which seem to be a bit better), medium hard tamps, nutating motion (which was quite good)
- finally I've tried various grind setting, normal flows, 4-6s delay between the end of preinfusion and actual coffee flow, ristrettos, extreme ristrettos
- different types of distribution, WDT, no WDT, NSEW, Stockfleths

No matter what I did I always got side channeling, only a couple of times with nutating motion the extractions were pretty even. I mean why the hell is it so hard to get a decent shot with this machine?

With lower doses I always get huge holes in the middle of the coffee cake, or near the sides of the basket, with higher ones it's usually none, or near the sides, although I still see channeling in the flow (like on the video).

Help...

Cheers,
dsc.

PS. would making the gicleur hole a bit smaller help?

[HB]

I mean why the hell is it so hard to get a decent shot with this machine?

You've clearly given the techniques and equipment calibration angle careful consideration. Tell us a bit more about the coffee. Is it a known performer? Some coffees don't create enough fines, which makes for difficult pours, especially some single origin coffees. Other espresso blends are fussy until they've rested for a week or so.

[dsc]

Hi Dan,

I think I tried just about everything, still I get water flowing down the sides of the basket which results in side channeling:|

As for the coffee it's an espresso blend from a roastery called Monmouth. They are one of the best roasters in London and I bought the coffee I use now last Sunday, so it's roughly 10days old (assuming it was around 2-3 days old when I got it). I know people from a European forum TMC use it quite often and say it behaves really well during extraction. I have also tried various other types, mostly SOs, but also two or three espresso blends fro HasBean (really good UK roaster). They all behaved the same, pretty nice start and blonding around the 17-18s.

Because it seems like nothing works anyway today I decided to take on a different approach and tamp only the sides, leaving the centre almost untamped. My convex Torr is made for this as I can to the nutating motion without the tamper getting stuck in the basket. I tried that and I was amazed to see nothing coming out of the basket for the first 30s. Usually on this grinder setting I get a stream almost after the preinfusion is finished, but now nothing was even dripping. After roughly 30-35s first drops began to appear and a thin stream formed after 40s. The stream was moving around the hole of the PF, but still it was black almost all the time. It was an extreme ristretto, lasting for 90s or even more, a bit off tastewise, but still amazing that it didn't go blond.

This this whole episode made me think of making a tamper which would look like this:



so a sort of 'negative' convex instead of the usual 'positive' convex tampers. It might have a flat area near the sides to tamp the edges better.

Has anyone ever tried something like this? I seem to recall someone posting a similar picture, but I cannot find it anywhere.

Cheers,
dsc.

[CafSuperCharged]

That temperature of yours 91C (195.8F) could in fact be too high.
Italian espresso lore says 88C +/- 2C. And you are above that.
Now on the coffee bed the temp may be a bit lower, but still too high for your coffee.
My previous coffee would only render its deliciousness at around 91C (in PF spout), the current coffee really must be in the 86C~88C range.
The coffee you mention does not ring a bell, temperature-wise.
I guess especially when the temperature is too high, oils/fats (lipoproteins?) break down faster and the stick effect I experience between the side wall of the basket and the grind may not occur.
Think about the pressure of the steam boiler that could be so high that the group actually becomes slightly overheated relative to your coffee's tolerance. Would your flushing cool the group/PF as fast as your reading in the group nut hole?

Also, have you considered a flat tamper? Another pressure, say like 35 kg?
Or, not tamping at all?

What about pump pressure? My Andreja Premium was delivered with pump pressure at 11.5~12 Bar. Reducing the pressure also reduces the flow (more water goes back into the tank through the OPV and less to the coffee).

What about freshness of the coffee. This could be a big deal in a blend when its constituents age differently.
What about the coffee's relative humidity?

It seems like you know what you are doing, yet I still would say, try to go back to the basics first.

Regards
Peter
Netherlands
Europe

[BobS]

From everything you described, you've tried various down doses, but haven't updosed. Also, the double
basket - is that the original?

Probably not worth much, but here's the technique I use -

- 18g Synesso double basket (made a bigger difference than the original double basket)
- Grind and fill to a rounded top
- Groom with modified Stockfleth's move
- Straight finger cut (about 17g) or curved finger cut (about 18g)
- Alignment tamp (less than 20 lbs) to insure level, small polish, no pressure
- 30 lb final tamp
- Wipe off excess coffee (don't turn over)
- flush to either 206 or 195 depending upon coffee
- Lock in portafilter
- If 206, dump pre-heat water out of cup, wipe dry, wait for heater to go off, pull shot
- If 195, dump pre-heat water out of cup, wipe dry, wait 45 sec, pull shot

Other - Brew pressure 9.25 of portafilter gauge, 10 on built in pressure gauge during shot pull.

Bob

[dsc]

Hi guys,

when we talk about 88*C+-2*C are we talking about the brew temperatures or actual output coffee temperatures? Because if you put a TC in the spout it reads around lower than the actual temperature of the brewing water (obviously as there's heat loss), but also it drops kind of fast during the first second of the extractions. This is why some people think that the HX bump profile is good for espresso, simply to keep the output coffee temperatures at a steady level.

As for the temps on the group you are right they might be a bit high, still lowering them won't do much with side channeling.

The stick effect you are talking about Peter is in my opinion caused by side channeling, as the coffee near the sides is more 'used up' and the centre is much less extracted and still holds together pretty well.

I have tried heavier tamps and it seems to be working but honestly I prefer the taste of lower doses and lighter tamps. It's sort of 'lighter' and delicate, comparing to the more 'brute' and slightly more bitter 30kg+ tamping. I have yet to try not tamping at all, I might do that tomorrow, using the shower screen as the tamp surface.

The problem I have with my machine is that it's awfully hot, it tops at 102*C after 45min in idle and I have to flush around 160-180ml of water to bring it down to 90*C. It also rebounds very fast after only 10s heating levels of 95*C or so again. That's of course on the group itself, as the temperature on the shower screen is around 2-3*C less. Don't know how fast the group cools down and I don't even know what temperature it is when pulling a shot or before starting the cooling flush. I doubt it cools much as it's a big chunk of metal with high thermal capacity.

Pump pressure is what it is, probably around 12 bars or so, but the OPV brings it down to 9bar. Flow rate is what it's supposed to be according to the measurements I did recently and the characteristic of the pump - 300ml/min.

As I said the coffee is around 10days old, so it's not that bad. I did check other coffees as well, in a range of 2-3 days after roasting, up to 20 days and more, all giving the same effect - side channeling and early blonding. I have no idea about it's relative humidity unfortunately.

The basket is a Synesso double ridgeless and it's pretty much comparable to the original ridged one. I've talked to someone who had a similar machine and he said that indeed updosing helped, but the difference in the taste was quite bad. I have tried doses of up to 16.5g and it seems to be the right thing, not touching the shower screen when locking the PF in, but giving a shower impression after the extraction. I'm afraid putting more coffee into the basket would make the PF hard to lock, but I might be wrong. Won't hurt to try though.

Thanks for your help and support guys. I'm slowly losing hope as I have tried so much and still it doesn't work. Funny thing is I tried that side only tamping again, with my grinder set to a coarser grind and still it took 20s to get first drops in the cup. It seems like earlier most water was running down the sides, sort of rising the coffee cake during the extraction, thus resulting in early blonding. I moved the setting to coarser a bit more and will check the results tomorrow.

Cheers,
dsc.

[BobS]

Hi guys,

Thanks for your help and support guys. I'm slowly losing hope as I have tried so much and still it doesn't work. Funny thing is I tried that side only tamping again, with my grinder set to a coarser grind and still it took 20s to get first drops in the cup. It seems like earlier most water was running down the sides, sort of rising the coffee cake during the extraction, thus resulting in early blonding. I moved the setting to coarser a bit more and will check the results tomorrow.

Cheers,
dsc.

This last part keeps bugging me. Just for grins is there water coming out near the center of the
shower screen?

As to dosing and tamping have you tried the Heather Perry moves - not the dosing up, but two downward
bumps on the portafilter after dosing to settle, groom, then tamp? She tamps fairly light, but tamping
heavy is fine.

As a test, pop in the single basket, use 7 g of coffee, adjust the grinder, grind, tamp, and pull a shot.
If it's basket or portafilter related, the results may change.

Any chance you could get your hands on a naked portafilter? Borrow someone's?

Bob

[BobS]

A few more questions -

- How old is the machine?
- Any parts replaced/repaired, beside the one valve?
- When was the last time it was descaled?
- By chance are there any water drops coming out of the lever while brewing, especially when stalled?

Bob

[HB]

so a sort of 'negative' convex instead of the usual 'positive' convex tampers. It might have a flat area near the sides to tamp the edges better.

Has anyone ever tried something like this? I seem to recall someone posting a similar picture, but I cannot find it anywhere.

You may be thinking of the rather poorly-regarded concave Gourmet Espresso Tamper.

I don't put much weight on the tamp's contribution to exceptional espresso, nor do I look at piston fit, shape, or tamp pressure as prime suspects when things go awry. To me, everything you've described so far says "it's the coffee." You can tweak your technique (updose, grind finer, nutating tamp, lower brew pressure), but most of those are methods of squeaking performance out of a coffee that's past it's prime.

That's my story and I'm sticking to it.

PS: If you wish to obsess a bit more, check out Dave's Tamp and Dose Techniques Digest.

[HB]

Thanks for your help and support guys. I'm slowly losing hope as I have tried so much and still it doesn't work.

I've had days like that. My solution is to blame it on espresso gremlins, put all the gauges, thermocouples, scales, and whatnot aside to focus on the "Zen of Espresso." Remember this is supposed to be an enjoyable hobby, not a man vs. machine death match. After a couple days of focusing on small victories (e.g., doing a "dump shot" to quell bitterness or short shots to reduce sour/blandness), the cloud passes and all is well with the [espresso] world again.

If you're really frustrated and just want an easy pull, drop the brew pressure to 6 bar. It's the equivalent of hitting a Wiffle ball - it doesn't go as far as the real thing, but you can't miss either.

[mhoy]

Does the water come out of the group head evenly? Perhaps it's backed up with goo. I'm assuming you back flush, but perhaps it needs cleaning up there.

Mark

[dsc]

Hi again,

This last part keeps bugging me. Just for grins is there water coming out near the center of the
shower screen?

Yes water is coming out evenly and in addition I have recently removed the screen, unscrewed the water jet, cleaned it and put it back together.

As to dosing and tamping have you tried the Heather Perry moves - not the dosing up, but two downward
bumps on the portafilter after dosing to settle, groom, then tamp? She tamps fairly light, but tamping
heavy is fine.

Tried that as well, I was bumping the PF since the beginning, but when all the problems started I simply stopped doing that as I was pretty sure that's causing some channeling (although I don't believe it is, but still I decided to not do it).

Will do a single basket test today and check whether the problem is basket related. Because I am a bit frustrated I will also buy an NPF this week and try to see what's going on.

- How old is the machine?
- Any parts replaced/repaired, beside the one valve?
- When was the last time it was descaled?
- By chance are there any water drops coming out of the lever while brewing, especially when stalled?

I've had it for 5 months or so, but it was bought used from a local coffee equipment company. It was given a full test and check before sending it to me and I believe it was descaled. It looks quite new, used for maybe a couple of months before I bought it. It was found by the company people somewhere in their new building that they have started renting recently (the previous company that was placed there was also a coffee business). All the parts are original, the valve was also ok, I just descaled it and put it back together. No water leaks/drops or anything like that when it's brewing/idle. I'm planning to do a second descale sometime soon.

I don't put much weight on the tamp's contribution to exceptional espresso, nor do I look at piston fit, shape, or tamp pressure as prime suspects when things go awry. To me, everything you've described so far says "it's the coffee." You can tweak your technique (updose, grind finer, nutating tamp, lower brew pressure), but most of those are methods of squeaking performance out of a coffee that's past it's prime.

I agree that tamping isn't high on my list of important things in espresso, that's why I prefer dosing less, grinding finer and light tamps. As I mentioned before I tried various different coffees, most of them coming from HasBean, so I'm sure they are fresh. All have given me similar results, with early blonding and water going down the sides. Now I'm curious whether this will show on the NPF. I hope so, so at least I'll be able to say that I'm not crazy:) Just for fun I will put away my TC and try to brew as I used to.

Remember this is supposed to be an enjoyable hobby, not a man vs. machine death match.

Tell me about it, it's been a struggle for me since the very beginning:|

Does the water come out of the group head evenly? Perhaps it's backed up with goo. I'm assuming you back flush, but perhaps it needs cleaning up there.

Cleaned it all recently and yes it gives an even flow, with 5-6 streams forming on the screen.

Cheers,
dsc.

[CafSuperCharged]

when we talk about 88*C+-2*C are we talking about the brew temperatures or actual output coffee temperatures? Because if you put a TC in the spout it reads around lower than the actual temperature of the brewing water (obviously as there's heat loss), but also it drops kind of fast during the first second of the extractions. This is why some people think that the HX bump profile is good for espresso, simply to keep the output coffee temperatures at a steady level.

As for the temps on the group you are right they might be a bit high, still lowering them won't do much with side channeling.

My understanding of Italian caffè standards is this is brew temperature. Serving is in the sixties (C). I do not think HX bump is bad, the question still is though, how high it should be and why Italians do not prefer to be first in line at the coffee bar ... (almost all, including large commercial, machines will have some heating issue during idle, the design of the machine determining how much higher the boiler must be above actual desired brew temperature for the longest part of the shot; also, after idle time, typically deposit builds in the bottom of the commercial PF).

The stick effect you are talking about Peter is in my opinion caused by side channeling, as the coffee near the sides is more 'used up' and the centre is much less extracted and still holds together pretty well.

Interesting. I cannot say I notice blonding, certainly not early in the shot, and would think I stopped the pump before my shot actually gets there 90% of cases. (aside: I am used to first stop the pump at first E/61 valve click down, and next let the pressure ramp down whilst coffee still pours. Next carefully move E/61 handle down to open three way valve and let last pressure in PF+head escape.)
With very fresh coffee the trickle has more volume and may play a bit more than in other cases. Another thing is to define blonding. Depending on the blend (and temperature critical) there will be red spotted crema output, this will stop building first, the trickle becomes a bit lighter, but there is no change in the color of the pour on the surface of the espresso. At some point you would see a light spot building in the surface of the crema - over-extracted.

I have tried heavier tamps and it seems to be working but honestly I prefer the taste of lower doses and lighter tamps. It's sort of 'lighter' and delicate, comparing to the more 'brute' and slightly more bitter 30kg+ tamping. I have yet to try not tamping at all, I might do that tomorrow, using the shower screen as the tamp surface.

What you describe is you have an Italian style preference over US style (coarser grind, overdose, take real care of distribution, tamp heavily).
IMO you must revert to the double basket that came with the machine now.
Watch out there may be national differences in details of machines. Commercial machines in my country are often set in order to do a drip filter type of coffee from an espresso machine (egads), influencing temperature, gicleur, etc. The question is if your QM Andreja Premium is really that or a QM 0980, and what, e.g. based on Polish importer spec, local modifications have been made.

The problem I have with my machine is that it's awfully hot, it tops at 102*C after 45min in idle and I have to flush around 160-180ml of water to bring it down to 90*C. It also rebounds very fast after only 10s heating levels of 95*C or so again. That's of course on the group itself, as the temperature on the shower screen is around 2-3*C less. Don't know how fast the group cools down and I don't even know what temperature it is when pulling a shot or before starting the cooling flush. I doubt it cools much as it's a big chunk of metal with high thermal capacity.

I reduced boiler temperature (pressure) because I don't do milk drinks. Flushing is much less critical, although I find I may need to actually flush longer.
Do you watch the temperature profile during the shot - could you share that with us? It could be the water in the tube towards the PF seems cooled relatively fast, however the group still contains lots of stored heat, causing ramp up during the shot?

Pump pressure is what it is, probably around 12 bars or so, but the OPV brings it down to 9bar. Flow rate is what it's supposed to be according to the measurements I did recently and the characteristic of the pump - 300ml/min.

Where do you read the 12 Bar? I compared my built in manometer with a professional one on a PF and the read exactly the same (built in being smaller causing larger error of reading - I know).
I would suggest to reduce that a lot on the OPV so you get between 9 and 9.7 (a.o. dependent on boiler heater cycle). The silicone tube easily comes off the OPV, which you must do in case several rotations are needed (my case similar to yours). I left the machine on during adjustments, but with live 230V parts inside that is at your risk/discretion. Watch out to not empty the water tank inside your machine when taking a tube off.

The basket is a Synesso double ridgeless and it's pretty much comparable to the original ridged one. I've talked to someone who had a similar machine and he said that indeed updosing helped, but the difference in the taste was quite bad. I have tried doses of up to 16.5g and it seems to be the right thing, not touching the shower screen when locking the PF in, but giving a shower impression after the extraction. I'm afraid putting more coffee into the basket would make the PF hard to lock, but I might be wrong. Won't hurt to try though.

The Synesso will be larger diameter, cylindrical wall (I assume) and a bit deeper. I would initially go back to the original Faema style double basket (and forget about a single basket until you found the sweet spot).

Regards
Peter
Netherlands
Europe

[Elbasso]

DSC,

I've just been where you are now. Andreja was almost flying out the window. The solution to my and maybe your problem was in the basket. During my Schomeresque cleaning frenzy I regularly cleaned my basket with a green scrubby. This enlarged the holes on the outside of the basket causing the exact same problems as you describe. Channeling, early blonding etc. Try a new basket, see if it helps.

elbasso

[dsc]

Hi everyone,

At some point you would see a light spot building in the surface of the crema - over-extracted.

It's a bit tricky sometimes as the lighter stream of coffee can go underneath the crema already in the cup, thus not 'blonding' the surface for some time. But generally I agree and I tend to stop my shots so that I only get brownish/redish crema with no lighter spots.

The question is if your QM Andreja Premium is really that or a QM 0980, and what, e.g. based on Polish importer spec, local modifications have been made.

My profile doesn't say that but I'm currently living in the UK and the machine was probably produced in Europe, given a UK plug and anything else it needs to survive 230V (wiring and electrical elements).

Do you watch the temperature profile during the shot - could you share that with us? It could be the water in the tube towards the PF seems cooled relatively fast, however the group still contains lots of stored heat, causing ramp up during the shot?

When I flush it takes roughly one cappu cap to cool the machine down (180ml), the temperature on the group drops to 90-91*C. During the shot it tends to go up a bit, stay on a steady level for 15s or so and than very slowly goes down. So it's a gentle HX bump I would say. I have no idea how much heat the group holds and I believe it might be quite hot because of all the hot water running through it during the cooling flush.

Where do you read the 12 Bar? I compared my built in manometer with a professional one on a PF and the read exactly the same (built in being smaller causing larger error of reading - I know).

I wasn't too clear about it, sorry for the confusion. The OPV is set to around 9bar so I get a reading of ~9bar on the brew pressure gauge during the extraction. With that 12bar I just meant the the pump goes up to it's maximum pressure, whatever it is and the OPV simply cuts it down to 9bar.

The Synesso will be larger diameter, cylindrical wall (I assume) and a bit deeper. I would initially go back to the original Faema style double basket (and forget about a single basket until you found the sweet spot).

I compared the two baskets and they are almost the same, except the ridge and the fact that the original one narrows down 2-3mm lower.

elbasso -

thanks for your suggestion but I never scrub down my baskets and it's brand new anyone, so it can't be the size of the holes.

Today I tried the 'no tamp whatsoever approach' and it seems to be working quite well, maybe except for the mess in the basket after the extraction:



Still I get huge channeling holes in the puck. I will try a very light tamp today and see if it changes anything.

Cheers,
dsc.