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Thread: 'Going Pro' on EM6910: Pressure Readings & Dosing.

  1. #1
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    Unhappy 'Going Pro' on EM6910: Pressure Readings & Dosing.

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hey all,

    Short-time lurker, first-time poster.

    I've had my EM6910 with EM0480 for years - I inherited it from my dad who's good at squandering money on things he doesn't use to my benefit. For the most part, I've been happy with the coffees I've been creating...until recently. Now I'm tired of my inconsistency, flat-flavours and resorting to coffee shops.

    I'm fairly sure I've covered off most bases on previous posts about this machine. I'm also fairly sure I've got the 2nd revision of the machine (stainless steel PF). I've only ever had and used the double-walled baskets.

    To 'go pro', I've ordered single-wall Marzocco (LM) baskets from EspressoWorkshop.com.au. The reason I went LM is that I read they fit and I wanted smaller baskets than the SB ones (I read that they like updosing to the 19-20 g mark!). Unfortunately, I received a 17 g basket instead of a 14 g basket. I also ordered the 7 g single LM.

    I've removed the plastic 'Graeme' in the PF (but I found that you need it in place if you use double-wall baskets as otherwise, it sprays everywhere!).

    I've been playing around with them this morning using stale supermarket Vittoria beans (4 months old) to practice. My machine registers a pressure reading at the marked sweet spot on the gauge when using an empty double-walled filter basket, and this is where I'm targeting.

    These are my findings:


    • Started with the 17 g: dosed 17 g and didn't even register a pressure reading on the gauge!
    • Dropped the grind to the lowest possible setting (0; it was on 5): still no reading.
    • Tried tamping harder (30 kg instead of 15-20 kg on bathroom scale): still no reading.
    • Upped this to 20 g & did the 5 c coin check - no imprint, small reading.
    • Gave up on wasting coffee in the double and started playing with the 7 g to try and register a normal reading.
    • Initially tried 7 g: couldn't even tamp properly as the coffee level sat past the point where the basket funnels.
    • Upped to 16 g (in increments until leveled coffee looked at right height, then tamped) & did the 5c coin check: too much (coin completely pressed into puck). Ran it anyway - registered good (but slightly high) pressure.
    • Next trial: drop the dose in the single to 14 g & try again.


    My concerns & questions:


    • I seem to need to really up-dose even in the LMs. I've read elsewhere that you need a smaller tamper to tamp the single LM as normal doses level out past the point where the basket funnels inwards. However, wouldn't this mean that you aren't dosing enough coffee into the basket to register a 5c coin imprint? Is this imprint necessary for correct dosing of a basket?
    • Is my lack of pressure readings and need to up-dose a result of a grind which is too coarse? I know this is a common issue with the EM0480, and I plan to add another spacer (just ordered two spacers): is this wise?
    • Is there anything I am not doing to explain why I need such a large dose to get pressure readings?!?!


    I have to say that I've found this forum to be extremely helpful in learning about the art of brewing an espresso. Thanks to all those who've put in, and I look forward to a little more!

    Thomas.

  2. #2
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    Quote Originally Posted by parktho View Post
    Hey all,

    Short-time lurker, first-time poster.

    My concerns & questions:


    • I seem to need to really up-dose even in the LMs. I've read elsewhere that you need a smaller tamper to tamp the single LM as normal doses level out past the point where the basket funnels inwards. However, wouldn't this mean that you aren't dosing enough coffee into the basket to register a 5c coin imprint? Is this imprint necessary for correct dosing of a basket?
    • Is my lack of pressure readings and need to up-dose a result of a grind which is too coarse? I know this is a common issue with the EM0480, and I plan to add another spacer (just ordered two spacers): is this wise?
    • Is there anything I am not doing to explain why I need such a large dose to get pressure readings?!?!


    I have to say that I've found this forum to be extremely helpful in learning about the art of brewing an espresso. Thanks to all those who've put in, and I look forward to a little more!

    Thomas.
    Hi Thomas

    I deleted all bar your questions to save space. Where to start?

    1) Your 480 must need shimming (badly). Although not recommending you go to the extreme of a full calibration, a 480 should be able to completely choke a LM Linea (think Mack truck of espresso makers) a few steps before its finest setting. Until your 480 is shimmed "within range", nothing else can work. The LM baskets are a ridged version of the VST ridgeless, and have different characteristics again. Assuming your standard SB baskets need to be at or near "13" (note: the standard SB480 setup is stated as "11 to 16" for espresso), the VST ridgeless will be correct closer to "8" or "9". A really large change! That will also get your dosing within the ball park (your third point) so you can start making sense of the rest of your issues.
    2) The 6910 pressure reading is a bit notional, and varies quite a lot from machine to machine. I have to assume your pours are also gushing... Within the same machine, I have found the gauge to be consistent even if the actual reading may be anywhere. I use the gauge mainly for highlighting different grind / dosing /tamping clearly using the same basket when setting up a machine for a new batch of coffee. FWIW, naked p/f / ridgeless VSTs usually read a little higher. Circa +one o'clock difference is the "new normal" once optimised compared to standard SB baskets.
    3) A VST 7 dosed at 7.2g (my optimum for my gear / roast etc) is at least 2mm "below the shelf", more like 4mm with some roasts: no way can a standard tamper fit in there! A Smartwater lime & guava 500(?)ml plastic bottle was the only thing I found that fitted properly - I am sure there are other alternatives. I used it about 1/3 full of "dumb water" to get the balance a little closer.

    Once you have sorted out the grinder, please let me know how you are getting on.

    Merry Xmas (picturing you toiling over shims...)

    TampIt

  3. #3
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    First: no pressure even though it reads with empty basket means your grind is not fine enough. If your EM0480 is already at 1 on the dial, you need the spacers. You can get a washer at Mitre 10 that is equal to maybe 2 or 3 of the shims Sunbeam has (or on ebay) and it goes under the lower burr. Each shim will give maybe 6 or 7 on the dial.

    Note the burr unscrews RIGHT HAND THREAD. Note also it has a small knob on bottom that goes back into a hole on the base - make sure any washer you use doesn't cover that hole.

    Use something to hold the 'stirrer' that sticks up while you use a small ring spanner on the nut. RH thread, OK?

    If the LM single is anything like the VST single, go buy one of those Lipton iced teas in a bottle, empty it and use the top of the bottle as a tamper - with bottle attached of course.

    You will get a lot of reaction on here about supermarket beans - ignore it, nothing wrong with using el cheapos to get your process right. What you miss with them is the superb flavours and the thick crema - they will still make a drinkable coffee when you get the process right. Note you will decide 'drinkable' gets redefined once you have correct process AND fresh good beans.

    But to get the machines working as they should, Vittoria are fine.

    EDIT: Hah! You got me and Tampit...

    My pressure gauge always read at the top of the coloured part for the best coffee - at the middle of the yellow/green the coffee gushed and tasted pretty crappy.

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    Question

    Thanks for the prompt responses, and sorry to post again so soon but I'm impatient waiting on the shims!

    I tried 14 g in the single later and got slightly low on my target for pressure & no imprint from the 5c coin. I eyeballed the time - approximately 18 s from when the stream started coming through (i.e. not counting the prefill) - is that what's considered a gusher?

    I will go up to 15 g from this result, and effectively use my single as a double until the shimming.

    A couple more queries:

    Is it necessary to fill the baskets such that a 5 c coin leaves an imprint? Is it better to just fill the basket using the dose that the basket is manufactured for (i.e. 7 g for the single, 17 g for the 17 g) and work on grind? It will not be possible to fill 7 g (or even 9 g) in the single and get an imprint. I thought I'd copy a pic of the single (part number L115/A) just so that we're on the same wavelength (can't seem to upload one of my own?!?):

    My pucks are wet & sloppy on top, although as opposed to when I was using double-walled baskets, they knock out mostly in one piece. Is the wet puck another symptom of the grind?

    Anyway, I'll try not to post again until I get my grinder shimmed, but I'm trying to make the most out of time I have on holidays whilst I wait for my wife to churn our first born out.

    Thomas.

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    Sorry for the long pause - hope things are going/went well with the bub. Congratulations - if you can get your coffee right it will be a great help in the coming months...

    Did you get the shims? How has it been with them?

    Don't worry about the puck - what matters is the coffee. Generally mine were quite dry but also I had some that had a layer of liquid on top. Interestingly it seems to mostly be on the decaf the missus drinks.

    I used the 5c test back before I got VST's - works OK but I found I did better if I dosed about 4mm down from the rim, which would never leave an impression - probably not even with a $2 coin.

    The 18 sec cup sounds like a bit of a gusher. The Sunbeams do a pre-infusion and your coffee should take around 25secs from that pause after that. I'd imagine the coffee was a bit weak in flavour and probably had little if any crema.

    The single baskets are a bit of a pain - that shelf means you need to know exactly what you're doing. Maybe stick with the double until you get everything nailed? TampIt has good advice on them - by the time I got to doing my first singles I had it pretty much nailed 2nd cup in.

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    Thanks for the reply. I'd typed a response on my phone, but I somehow lost it!

    I've definitely improved since my last post. I've added three additional shims to the grinder now (a total of six). I'm now getting good 25-30s pours at a setting of 11/12. Interestingly, for the supermarket coffee, I had to use a setting of 9 to get a good pour - is this the result of the coffee being old or more likely just a different bean? I'm now using pretty fresh coffee from the markets.

    Another 'cool' thing - on my first few pours using the fresh coffee, the grinder was still on 9 and so I really overextracted - it took well over a minute to run, but interestingly, there was a clear layer of oil on top of the shot.

    I can get the single to work using a fruit juice cap as suggested. But mostly I don't bother as it is too weak for me. That said, the 17g is too strong for me and I don't have a 14g, so I simply pour off a little of the shot.

    I consistently use 17g (I put our kitchen scales under the grinder and run the grinder into a container until 17g) and I adjust the grind mainly for a good pressure reading (which is also usually a good timed shot). I'm not confident on the whole 'blonding' thing yet to go by this.

    I haven't changed my frothing technique, so I think I've found that the milk blends better with a better shot (compared to my coffees of old, I'm getting better finishes to the froth).

    Pucks have been less wet, and I made myself a knock box from 150mm PVC.

    The coffees have been helping with our newborn Benjamin, so thank you very much.

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    Quote Originally Posted by parktho View Post
    Thanks for the reply. I'd typed a response on my phone, but I somehow lost it!

    I've definitely improved since my last post. I've added three additional shims to the grinder now (a total of six). I'm now getting good 25-30s pours at a setting of 11/12. Interestingly, for the supermarket coffee, I had to use a setting of 9 to get a good pour - is this the result of the coffee being old or more likely just a different bean? I'm now using pretty fresh coffee from the markets.
    Hi parktho

    Two things there -

    firstly, that many shims will settle as they bed in - sometimes really quickly. The 11/12 setting is about "espresso middle", however as long as you are within the range 0-25 it really doesn't matter much (unless you also do plunger / aeropress etc). You may find the shims settling take up to three off the setting.

    secondly, supermarket coffee is a coarser grind than espresso - if the shims aren't bedding in, the reading of 9 makes no sense... unless you also changed the dosing.

    Quote Originally Posted by parktho View Post
    Another 'cool' thing - on my first few pours using the fresh coffee, the grinder was still on 9 and so I really overextracted - it took well over a minute to run, but interestingly, there was a clear layer of oil on top of the shot.
    Uh oh, oil on the top is usually (not always!) a sign that the grinder needs a good clean or the burrs are shot. Given your earlier posts, better check the particle spread (white paper test). If the burrs are gone (... you said a few years old) then you will not get a really good coffee until you replace them. FWIW, the 480 burrs are very long lasting for such a cheap conical grinder.

    Quote Originally Posted by parktho View Post
    I can get the single to work using a fruit juice cap as suggested. But mostly I don't bother as it is too weak for me. That said, the 17g is too strong for me and I don't have a 14g, so I simply pour off a little of the shot.

    I consistently use 17g (I put our kitchen scales under the grinder and run the grinder into a container until 17g) and I adjust the grind mainly for a good pressure reading (which is also usually a good timed shot). I'm not confident on the whole 'blonding' thing yet to go by this.
    Try to dose the single basket at 7.2g and then alter the grind until it takes circa 35 seconds AFTER preinfusion (i.e. time it from when the first drops appear). If it is still too weak, the roast is probably stale! As a latte, I use my VST single (kinda LM without the ridge) with 100g to 110g of full cream milk (before frothing). It fills a 250ml glass and it has plenty of "bite". Mind you, if your 480's burrs are gone, it will be unbearably bitter... Hopefully not, however then you need to replace the burrs asap and then reshim it.

    Quote Originally Posted by parktho View Post
    I haven't changed my frothing technique, so I think I've found that the milk blends better with a better shot (compared to my coffees of old, I'm getting better finishes to the froth).

    Pucks have been less wet, and I made myself a knock box from 150mm PVC.

    The coffees have been helping with our newborn Benjamin, so thank you very much.
    "I've found that the milk blends better with a better shot" - Yep.

    "Pucks have been less wet" The later 6910 often adds a little water after the shot finishes (as does the 7000). Forget wet / dry puck. Much more importantly - does the puck come out in (more or less) one piece? Other than that, all a puck can sometimes tell you is evidence of channeling.

    Enjoy your cuppa


    TampIt

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    As a set of new burrs is around $90, can you tell me what worn burrs look like? Next time I disassemble, I will post a pic.

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    Quote Originally Posted by parktho View Post
    As a set of new burrs is around $90, can you tell me what worn burrs look like? Next time I disassemble, I will post a pic.
    G'day parktho

    Still waiting for the pics... Hopefully cleaning it out sorted it.

    TampIt



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