Elektra T1 - trouble with channeling / early blonding

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dsc

#1: Post by dsc »

Hi guys,

as mentioned before I'm having problems with the extractions on my Elektra, pretty much since day 1. I'm using small doses, 14-16g, usually 3s preinfusion with 1bar and 8.75 applied throughout the shot. Normally it starts well, but goes sideways near the end, like here:
goes blond pretty quickly and the flow isn't as calm as it should be. It's channeling pretty badly, especially the last 5s of the clip, but that's how it is with most coffee (although with most I only get the occasional bright spot here and there). The blend I'm using now is from a London roastery called Monmouth and is less than 2 weeks old. You can also see that the cone that forms is very shallow, far from the stuff you usually see on a naked portafilter.

Now tastewise it's not too bad, pretty balanced, quite sweet even, but I'm curious why pretty much every coffee goes blond so fast? Recently I made a test dividing the shot into 3 cups and the last one was very watery, almost transparent.

Anyone care to comment?

Regards,
dsc.

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dsc (original poster)

#2: Post by dsc (original poster) »

Hi guys,

I've been having extraction problems for a while now (a few months I would say), very annoying thing, especially when you can't figure out why that's happening. Yesterday I tried something very simple and easy and it seems to have solved the problem, at least with the coffee I'm using now.

My usual routine when preparing a shot is something like this:

- dose straight into the basket moving it around while the grinder is working (it's a doserless Mazzer-E type of config)

- tap/thump the PF on the fork to settle the grounds

- tamp medium heavy (around 15kg?) or light, it depends really I usually try both and do a twist to remove all coffee from the piston

- lock and go

I tried various tamp methods (twist, no twist, heavy/light tamps and so on) but nothing was working properly. I was either getting thin, fast blonding shots or tight ristrettos which were almost choking the machine. Especially the beginning of the shots were very strange, super fast during the first second or so, then slow for a few seconds and very unsteady and unstable for the duration of the shot. It looked as if the fine particle were being pushed down during the first few moments, but before settling there wasn't enough resistance and water was shooting straight through the puck resulting in channeling and sprites. Remember this is only during the first 1-2s after which the flow would slow down, sometimes dripping, forming a very thin stream. The stream would normally blond after around 15-18s with additional sprites and sometimes heavy 'dancing'. Taste-wise each shot was definitely not right, usually harsh and too acidic, lacking body and simply thin.

Because I already tried various tamping methods I decided to omit the second step which is the tap/thump to settle the grounds. I ground the coffee as usual, the same dose, straight into the basket with a small heap in the middle. Tamped medium heavy and locked it in the group. The result was something I wasn't expecting, totally different pour, slow (even though I haven't changed the grinder setting), dripping for a good couple of seconds, forming a nice thicker cone and stream, not blonding for at least 25s, steady, stable. Tried the same again and got the same result. Taste-wise definitely better, more round, less harsh flavours, more body.

I know that I've only tried this with two shots and single type of coffee (SO) but I'm curious why such a difference? I've ready posts where people said that tapping/thumping the PF to settle grounds is good, heck I even saw it and had the best espresso in my life prepared this way (although it was from a doser fitted Anfim). Is it possible that my modified Major produces a proper 'mixture' of coarser and fine grinds which somehow gets messed up when disturbed? Still tapping/thumping would normally move fines further down, not up and so would slow down the extraction, so I'm a bit confused here.

Any suggestions/ideas appreciated.

Regards,
dsc.

andrewpetre

#3: Post by andrewpetre »

We should get the last chunk of this split out to techniques or some other forum (at least to its own "help me fix this" thread) where people will actually read and help diagnose your extraction.

I would have completely overlooked this older thread except that it was about the T1 in particular =)

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mhoy

#4: Post by mhoy »

How many grams? Perhaps grind finer and under dose?

Mark

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dsc (original poster)

#5: Post by dsc (original poster) »

Hi guys,

true about the last bit, but I didn't want to start another topic and decided to keep it all in here.

Mark I've tried both finer grind/low dose and coarse grind/higher dose, it was still far from perfect.To be honest I thought that the non-thumping would change something but the difference is marginal. The pour is simply very chaotic, the cone moves around a lot and almost never stays in the middle (and even when it does there's a lot of bad things going around anyway). I wouldn't worry if it was only the look of the extraction that's wrong, but it's actually bad taste-wise as well.

Regards,
dsc.

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shadowfax

#6: Post by shadowfax »

This has always been a perplexing problem, Tom. IMO a Major and T1 should perform better than you're experiencing, and I think if I were in your place I'd be suspecting a flaw in one of the two. I associate the way your pours look and your description of it with really dodgy or badly mounted burrs. I know you've said you replaced them, but are you sure that they're spinning true? have you checked the shaft? Is there a wobble?

If I were happy with that I'd put my doser back on and try dosing with that--just to make sure that the doserless mod isn't the culprit. A long shot, but it sounds like the kind of thing you're down to.

After that I'd be looking at my dispersion screen, how it's distributing water during a flush. If all that's good, I'd find a friend who could loan me a really nice grinder (hopefully a big conical, but in any case one that makes great pours on other machines) for a couple of days, and see if that improves things.

Beyond those diagnostic questions, what taste defect do you associate with these ugly pours?
Nicholas Lundgaard

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dsc (original poster)

#7: Post by dsc (original poster) »

Hi Nicholas,

agreed if someone told me a year ago that I would have a Major and an Elektra in my kitchen I would've never thought shite in the cup.

Things I'd like to try first before taking the rig down to the parking lot and running it over with my car:

- low dose vs. high dose - which is effectively checking how headspace affects the pours

- preinfusion vs. no preinfusion

- current dispersion screen vs. original dispersion screen (my current one has a bit of wire stuck between the mesh and the metal backplate)

- Macap vs. Mazzer - I still have my Macap and even though the burrs might not be superb I'm just curious what the result is going to be

Normally the answer to these kind of questions is 'go back to basics', so I will try to turn off the preinfusion and pack less coffee in the basket.

I've checked the burrs and they appear to be parallel, at least to some degree. I know that when they touch slightly it's not a constant noise like they're touching with the whole surface, but I've never heard a grinder that did this (I think they all touch partially). Perhaps it is a little bit off, but I don't think there's anything I can do about it. Can I somehow check their position, using home methods? I tried looking at it but the human eye is not good enough to check the position of fast spinning elements. I don't think there's wobble, but I will check again today.

I was thinking of removing the funnel and might do that if nothing else works. The dispersion screen is another suspect, I think there might be something wrong with how the water is flowing straight from the group. That or the preinfusion which is doing more bad than good, although you've tried it yourself and it wasn't too bad, was it? Of course a borrowed conical would be a handy tool to see what's wrong.

Taste-wise the shots just taste bitter and sometimes smell very strange. You know when you lean down to smell the shot that ended a few seconds ago it smells a bit like rubber/tire, synthetic. I was wondering whether it's because the temp is too high but I'm mostly brewing at 91*C-92*C and if I go below the shots are sour, acidic. I can't really get any real flavour from them, although a few days ago I had a shot which was awesome (at 92*C), lemon/sweet and not bitter at all.

The thing that worries me the most is how unstable the shots are. When I look at clips of various pours most of them seem very calm, dripping, forming a cone, slowly getting bigger. If I try to do something similar I choke the machine so that it drips all the time, or I get a 15s blond thin crap.

I will order 1kg of beans from HB (same blend) and do some debugging over the weekend.

Regards,
dsc.

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cannonfodder
Team HB

#8: Post by cannonfodder »

Odd. The Elektra machines are one of the easier machines to use IMHO. Meltdown shots are usually caused by the beans, grinder or barista. Assuming you are using good beans that leaves the grinder and and the Barista. Are you weighing your shots? Elektra's are very picky about head space, across their entire product line. Because the shower screen is attached directly to the dispersion block, there is no head space above the screen unlike your average E61 box which has a good ¼ inch of air between the dispersion disk and screen. A half gram to much/little will make a difference in the shot. A grinder that is off just a bit will also cause a torrent of problems. I am also assuming that the ugly shots are bitter and lacking body, a symptom of channeled shots.
Dave Stephens

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dsc (original poster)

#9: Post by dsc (original poster) »

Hi Dave,

strange indeed. Yes the shots are thin, lack body and are bitter (although they do have a fair amount of crema).

I do weigh the shots when I'm dialing in my grinder, but once that's done I trust the timer. I will check how much coffee it's packing now and how consistent it is.

Regards,
dsc.

zin1953

#10: Post by zin1953 »

I cannot explain it, as I've never had that problem either. But I think Dave's certainly offered good advice . . .
A morning without coffee is sleep. -- Anon.