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Thread: Early dark drops - Why?

  1. #1
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    Early dark drops - Why?

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hi,

    Once in a while when pulling a shot I notice a few dark drops of extract very early in the shot (only a few seconds into the shot).* At this point Id expect the pressure on the group is still building.* Normally the first drop of extract start at around 7ish seconds.* Although I havent seen this behavior for a while of friend of mine with a similar machine (NS Oscar) seems to get it quite commonly.

    Any ideas of the cause?

    Cheers

  2. #2
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    Re: Early dark drops - Why?

    I get this too. I think it could be fine particles of coffee getting pushed through the basket/puck. I do end up with a bit of very fine coffee grain at the bottom of my cup.

  3. #3
    Senior Member askthecoffeeguy's Avatar
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    Re: Early dark drops - Why?

    whens the last time you changed the seal? might not be a tight fit?

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    Re: Early dark drops - Why?

    I dont think its related to fines, but it may well be related to the grind setting??

    I better clarify.* The early drops come out of the normal spout (not out of the sides). My first thought was that they were due to residue water in the group handle (under the basket), but thats not the case.*
    Like I said it hasnt happened for a while now, but I thought it would be nice to know why it happens.

    So most of the time - pour is nice and thick and starts 5-7ish secs after hitting button.
    But sometimes for an unknown reason - the pour starts VERY early with thin dark drips.. it when then revert to a normal looking pour around the 5-7sec mark.

    Calling all experts ;)

  5. #5
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    Re: Early dark drops - Why?

    After talking to my friend that gets this alot it seems that he overdoses quite a bit. Ive asked him to lower his dose and see how it goes. Come to think of it since I corrected (down) my dose I havent seen this phenomenon - could be on to something.

  6. #6
    Senior Member askthecoffeeguy's Avatar
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    Re: Early dark drops - Why?

    do you insert the empty handle after each extraction and flush out the group head - if not could be a build up of stuff in there trying to get out!

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    Re: Early dark drops - Why?

    It happens (apparently) even when the handle is completely dry.

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    Senior Member artman's Avatar
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    Re: Early dark drops - Why?

    My machine did this for a while, You could see almost black drops initially in the entire bottom of the basket (naked handle), which quickly turned normal colour. Its stopped now, but was thinking what it was.

    Cheers

  9. #9
    Senior Member coffeechris's Avatar
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    Re: Early dark drops - Why?

    This happens to me if i dont flush out the group head first...

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    Re: Early dark drops - Why?

    Hi askthecoffeeguy,

    Thanks for all the advice. Do you mean flush out stuff from the group handle (i.e. the area under the basket) or in the group head itself (i.e. above the shower screen)?
    I always do a clean-out/cooling flush before pulling a shot. Generally Ill do this without the handle attached. Not sure about my friend.

    Thanks


  11. #11
    Senior Member artman's Avatar
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    Re: Early dark drops - Why?

    My machine always needs a cooling flush, I backflush after each session, and I am using a naked handle, the cause wouldnt be "dirt" in my case.

    Cheers

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    Re: Early dark drops - Why?

    Good to know artman. Definitely eliminates the water in the handle explanation.

    These dark drops must be produced while the coffee bed is being settled and pressurized, perhaps caused by poor distribution?

  13. #13
    Senior Member artman's Avatar
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    Re: Early dark drops - Why?

    I wouldnt say so in my case, I have been very consistent with my technique, and noticed them one day, then after a while noticed them gone. In hind sight, didnt think to check if it was a particular bean type though, maybe that was it?

    Cheers

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    Re: Early dark drops - Why?

    artman,

    Yeah Im very careful with my technique as well.* I would hope it was something as shameful as poor distribution* ;)

    One thing I was doing around that time was slightly over-dosing.* I have ridged baskets and the optimum coffee level my machine is just below the ridge.* I used to often dose into the ridge and this would often cause a pit to form on the edge of the puck (Im guess from excessive pressure). Perhaps it was related to this...

  15. #15
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    Re: Early dark drops - Why?

    If you end up with a great crema and coffee, why does anything need to be wrong or have been caused by something you felt may not have been done correctly?*

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    Senior Member artman's Avatar
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    Re: Early dark drops - Why?

    Quote Originally Posted by 4B7F687E65524E626B6B68680D0 link=1330306410/14#14 date=1330417398
    If you end up with a great crema and coffee, why does anything need to be wrong or have been caused by something you felt may not have been done correctly?*
    You are dead right. The coffee still tasted great for me, I was just curious when I noticed it occurring.

    Cheers

  17. #17
    Senior Member askthecoffeeguy's Avatar
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    Re: Early dark drops - Why?

    Quote Originally Posted by 58405249484F4D40554847210 link=1330306410/9#9 date=1330381468
    Hi askthecoffeeguy,

    Thanks for all the advice.* Do you mean flush out stuff from the group handle (i.e. the area under the basket) or in the group head itself (i.e. above the shower screen)?
    I always do a clean-out/cooling flush before pulling a shot.* Generally Ill do this without the handle attached.* Not sure about my friend.

    Thanks
    By that I mean inserting the empty group handle into the group head and running some hot water through it pretty soon after running the shot to disperse any grinds caught up there and to flush the group head

    this also happens to me occasionally - seems less of an issue if I drop say a half a cup of water through the group head prior to inserting the handle and running the shot - purge before and after each extraction - thats my moto!

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    Re: Early dark drops - Why?

    Quote Originally Posted by 79757C7C7F7F79726873691A0 link=1330306410/8#8 date=1330371730
    This happens to me if i dont flush out the group head first...
    Wise words, and yes, its mainly just curiosity - an unexpained mystery.* Doesnt hurt to figure out the cause.
    Quote Originally Posted by 7B69716E727F79757C7C7F7F7D6F631A0 link=1330306410/16#16 date=1330421966
    By that I mean inserting the empty group handle into the group head and running some hot water through it pretty soon after running the shot to disperse any grinds caught up there and to flush the group head

    this also happens to me occasionally - seems less of an issue if I drop say a half a cup of water through the group head prior to inserting the handle and running the shot - purge before and after each extraction - thats my moto!
    Thanks again for the advice.* But this still doensnt make sense to me since any left over grind stuck to the shower screen would still have to migrate throught the tamped coffee bed to end up as early dark drips....

    Anyway time to abort!* Thanks to all for trying.

  19. #19
    Senior Member GregWormald's Avatar
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    Re: Early dark drops - Why?

    Quote Originally Posted by 243C2E353433313C29343B5D0 link=1330306410/13#13 date=1330405704
    One thing I was doing around that time was slightly over-dosing.* I have ridged baskets and the optimum coffee level my machine is just below the ridge.* I used to often dose into the ridge and this would often cause a pit to form on the edge of the puck (Im guess from excessive pressure). Perhaps it was related to this...
    Given the above a possible explanation is:

    The pit could indicate channelling from an incomplete tamp as the tamper cannot tamp properly around the ridge. Once the beans start to swell, the pit closes up and the channelling stops.

    Greg

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    Re: Early dark drops - Why?

    Quote Originally Posted by 04312624142C312E222F27430 link=1330306410/18#18 date=1330433759
    Given the above a possible explanation is:

    The pit could indicate channelling from an incomplete tamp as the tamper cannot tamp properly around the ridge. Once the beans start to swell, the pit closes up and the channelling stops.

    Greg
    That makes sense to me.
    Regarding the pits however, I still used to get them after very careful distribution and tamping.* Since lowering my dose to just below the basket groove theyve disappeared.

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    Re: Early dark drops - Why?

    Of course, I havent got a nice machine, but I experiment a bit with how much I dose (the convenience of a cheap machine is there is no pressure release valve if I WAY overdose, not like the lovely Elen).*

    Anyhow, coffee is essentially black.* Crema is a frothing related to the oils extraction under pressure, or something like that, right?*

    Lets say out of a given shower, water streams at a certain pressure (SUnbeam claims 15 bar on mine) and hits the grinds.* If they are too small or too much or packed too tight, or any combination of these, then the pressure of the exiting stream can be GREATLY reduced.* If it gets reduced too much too quickly after hitting the grounds, then the extraction of oils may not be great in the initial bit of water passing through and you just get a trickle of... coffee... black... because coffee is black... okay, point made.*

    In my experimenting, if I over-dose, I REALLY over-dosed.* that meant that all I got was black drops.

    Yash, in your case, if you had blocked the pressure only by a little too much (and you are experienced enough that you arent likely going crazy, I think) then you may have got the black drops of over-fine/over-packed/over-tamped coffee for a few seconds.* Then, the grounds may have expanded as they should and the rest of the pour was able to pass through the puck with a steady pressure and do what its meant to.*

    As for what went wrong since your coffee routine is just that: maybe it was a high-humidity day and the grounds behaved differently.* Or maybe it was fresh beans that hadnt settled in yet - so they were grinding funny.* Those are the two reasons that could affect how the pour went through your grounds which are outside of your control vs. your grind / your dose / your tamp.

    Somebody give me some input since Im trying to figure it all out myself and this is a best guess based on what Ive read in this thread; on top of my home experience with a decidedly second-rate machine; as well as studying the workings of the lovely Elen (Mrs. Expobar to you!) at the office.

    Yash, I wonder if this hits the mark for you at all.

    ServingRoyalty
    is causing me to lose weight.

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    Re: Early dark drops - Why?

    Quote Originally Posted by 2B2B3B27262A234F0 link=1330306410/20#20 date=1330697712
    Lets say out of a given shower, water streams at a certain pressure (SUnbeam claims 15 bar on mine) and hits the grinds.* If they are too small or too much or packed too tight, or any combination of these, then the pressure of the exiting stream can be GREATLY reduced.
    Hi ServingRoyalty,

    Thanks for your detailed reply, and sorry for missing it. I dont quite get what you say about pressure being greatly reduced if the coffee bed is choking the machine.* If anything I would expect the pressure to increase to the maximum possible pressure of the pump or the setting of the OPV (over pressure valve).

    Makes sense?

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    Senior Member Rocky's Avatar
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    Re: Early dark drops - Why?

    I dont think I have ever seen the phenomenon you describe, but the only thing that makes sense to me is that maybe the initial seconds in the pour carry the finest particles of grind straight through. Once the puck has been saturated, the fine particles will still be there but they wont be discernable due to the more efficient extraction that is occuring.

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    Re: Early dark drops - Why?

    Behmor Brazen - $249 - Free Freight
    Water pressure straight out of the shower is one thing - the pressure the machine is pumping. However, once into the grinds, the pressure of the water doing the actual extraction is not the same, necessarily. That is to say: the water isnt flowing freely through the grinds - which changes as the grinds expand during extraction (and Ive noticed as the coffee gets farther from roast date).

    Of course, what Rocky has posted makes a lot of sense, too...



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