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Thread: Second shot disaster

  1. #1
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    Second shot disaster

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    I have a Gaggia Classic, Rocky Grinder and using Five Senses blends. I am extremely happy with the way my coffee skills have increased over the last 18 months, to the point where I can tell how the coffee is going to taste before I taste it. I very rarely have a bad coffee in the morning now, and my wife reckons that it has totally spoiled going out for coffee, as nothing (especially around Bunbury) compares with the coffees I turn out.

    Anyway, the issue I have at the moment is not being able to get a decent second double shot out of the Gaggia. I very rarely have to make four coffees, and don’t like to do so, as it stretches the steaming capability of the Classic to the max. But whenever I do, the second shot of espresso is always weak and ‘off’. It seems to rush straight through the puck, turning white almost straight away. There is no logical reason (that I can see) for the under-extraction to occur, as I have not adjusted grind settings, dosage or tamp between shots.

    I have a few friends coming over this weekend for dinner, and want to serve Affogatos for desert, so I need to refine my technique.

    I follow my routine exactly for each shot: grind, stir, tamp, flush, extract. But the second shot is always dodgy.

    Should I be cleaning and drying the PF and basket before the second shot?

    What about Temp control, how long to wait after the first shot is pulled, before I go with the second?

    Should I flush the group after the first shot, then grind and tamp the second?

    Anybody have any tips on getting a perfect second double shot?

    Cheers

  2. #2
    Senior Member Dennis's Avatar
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    Re: Second shot disaster

    Hi Spelunx and welcome to CS!

    I purchased a Classic recently (and have repaired a few) and really think these are great little machines.

    Can I ask if you are waiting for the ready light to extinguish (though some work the other way round), before pulling the 2nd round. I dont think theres a need to rinse the group handle in between, but a wipe out is a good idea.

    As for affogatos - quite a few people here prepare this well in advance and refigerate the extractions to be enjoyed later. Maybe you could try this - prepping in the afternoon will give you more time with your guests. ;)

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    Re: Second shot disaster

    Quote Originally Posted by Dennis link=1205285034/0#1 date=1205286142
    Hi Spelunx and welcome to CS!

    I purchased a Classic recently (and have repaired a few) and really think these are great little machines.

    Can I ask if you are waiting for the ready light to extinguish (though some work the other way round), before pulling the 2nd round. *I dont think theres a need to rinse the group handle in between, but a wipe out is a good idea.

    As for affogatos - quite a few people here prepare this well in advance and refigerate the extractions to be enjoyed later. *Maybe you could try this - prepping in the afternoon will give you more time with your guests. ;)

    It has been a great machine for me, thats for sure...

    Yes, I do wait for the red light to turn off again, but it seems to make no difference....

    So i can prepare the shots and put them in the fridge? How would this affect the flavour?

    Also, I like the way the ice-cream and the coffee melt together....


    Cheers


  4. #4
    Senior Member Dennis's Avatar
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    Re: Second shot disaster

    Im at a loss to explain what might be happening - perhaps someone with more experience with the Gaggia can pitch in.

    As for the affogato, I like it the way you do. Best way to find out how the refrigeration method works it tastes is to try it for yourself! ;)

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    Re: Second shot disaster

    The Silvia is similar in this respect. Water temperature drops between shots before climbing up again...sometimes overshooting.

    I havent used Gaggias but you should ensure that the temp is ready before pulling the second shot. (With the Silvia, I use a PID so have no issues but there are numerous articles about temp surfing).

    Your routine seems fine. I do clean my basket between shots (dont take too long to get ready the second shot as the PF and basket might cool down too much). I also flush slightly to get rid of loose grounds on the showerscreen before putting in PF for a second shot.

    Im assuming that your dosing is similar for both shots? It needs to be.

    Lastly, are you steaming between shots? Activating steam between shots will shoot the temp up big time.

    You could consider getting a PID if you want stability between shots.

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    Re: Second shot disaster

    The Gaggia is different to Silvia, due to less thermal mass/stability and the location of the thermostat.

    As the shot is pulled, and cold water flows into the boiler, the overall temperature drops. Greater thermal mass [inc volume of hot water] retards this process, but as shawn_low says it occurs in all boiler machines, but it is more drastic in the gaggia than the silvia.

    But interms of your second shot, whats more important is where the thermocouple is located.

    In the gaggia, it is located near the bottom of the boiler and right near the heating element. Therefore when the heater kicks in and heats the water, the water surrounding the thermostat will be hotter than for the rest of the boiler.
    The thermostat will respond to the temp surrounding it and cut off the heat, even though the total temperature of water in the boiler has not stabilised.
    In the silvia, its located near the cold water inlet and at the top of the boiler ie much further from the heater.

    I have seen a study for Gaggias that found the thermostat responds [ie cuts out the heating] at about 2 min after the shot....[hence you will see the light go out].
    But, it also found the overall water temperature takes a further 4-8 min to stabilise.
    It recommended a 4min minimum wait between shots for the gaggia.

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    Re: Second shot disaster

    Wow, thanks for the responses.

    Firstly, no I am not steaming between shots, I pull two doubles in a row and then try and build up enough steam to do the milk. I have found that by flicking the steam on for 30secs or so, blowing off some steam, then leaving it for another 30sec to a minute, I can usually get enough milk steamed for four cups. I also put away the Pavinas and drag out four smaller cups I have, which makes the job easier. It is not always successful, so i dont often make four cups.

    Thanks for the reply reubster, any chance of being pointed to the article for further reading?

    4 minutes between shots hey? Jeeze that is a long time! Perhaps I had better buy another Classic and just swap back and forth between the machines? :D

    Is there any way of cheating by using the steam switch? Perhaps 15secs of steam, followed by a flush, then a minute on normal thermostat?


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    Re: Second shot disaster

    Quote Originally Posted by Spelunx link=1205285034/0#6 date=1205377324
    Wow, thanks for the responses.

    4 minutes between shots hey? *Jeeze that is a long time! Perhaps I had better buy another Classic and just swap back and forth between the machines? * :D
    Get a Silvia. : ) Or better yet, splash out for a HX machine. Problem solved.

    Quote Originally Posted by Spelunx link=1205285034/0#6 date=1205377324

    Is there any way of cheating by using the steam switch? Perhaps 15secs of steam, followed by a flush, then a minute on normal thermostat?
    In theory this should be possible as your boiler temp will go up when you switch to steam. Im sure someone else has done studies as to how much the temp rises and when the optimal time is to pull the second shot. Surfing Gaggia!

    A cheaper alternative to a second or new machine is as I mentioned: get a PID. You will still have to wait between shots but if you want to cheat by flicking the steam switch, at least you will have a temperature readout in which to react to.

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    Re: Second shot disaster

    Spelunx

    The report is from a non site sponsor,
    send me a PM with your email address and Ill email it to you.

    Ultimately its based around a Gaggia/PID installation, so the 4min recommendation is probably the best time achievable.

    The steam switch could be used to further heat the boiler [once the brew thermostat cuts it out]. The problem is, if you go past the optimum boiler water temperature, you have to then wait for it to cool back down, that takes even longer again.
    Therein lies the other advantage of a PID, you can "see" what temp the boiler is at anytime.

    A common gaggia trick is to hit the steam switch midway through the shot. This overrides the brew thermostat and helps keep the shot temp more stable [it tends to drop through the shot otherwise].

    Plus, it keeps the post-shot boiler temperature a little higher, so the recovery should be a little faster.

  10. #10
    sdg
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    Re: Second shot disaster

    Surely if the report is informational its link could be posted for everyones benefit?

  11. #11
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    Re: Second shot disaster

    what is a pid

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    Re: Second shot disaster

    Quote Originally Posted by Raoul Duke link=1205285034/0#10 date=1205458711
    what is a pid
    Without going into scientific part of it (Im not the best to explain that either), its a controller device that controls the temp more accurately and less tolerance (give or take 1 degree instead of up to 10 degrees without a PID). The standard thermostat cuts the boiler out at 100 degrees and starts it at 88(?). Theres also temp overuns as the temp will still keep rising for a while when the boiler shuts off, same at the lower end. The PID keeps it to within 1 degree of the set temp. Thats the simple explanation *for it. For the more curious on how it works and the electronics behind it, please contact KJM.

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    Re: Second shot disaster


    Cheers guys.

    I have no real plans to PID at this stage, as the eventual plan is to upgrade to a Hx machine, sometime in the next two years.

    Although, reading the article on another "Coffee" type website, I am super-keen to get an old 60s machine and do it up!

    PM sent.

  14. #14
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    Re: Second shot disaster

    Another one with an early onset of Upgradeitis....

  15. #15
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    Re: Second shot disaster

    Quote Originally Posted by simone link=1205285034/0#9 date=1205457967
    Surely if the report is informational its link could be posted for everyones benefit?
    Hi Simone,

    Sorry, I dont have a link to said report, it was privately emailed to me by the supplier in question.
    Knowing the title/content/author etc, I have extensively googled searched it and was not able to find it anywhere.
    Whilst it is not copyrighted, its lack of posting/reference suggests [to me] that its author did not it intend it for the open public domain, so out of respect , Id prefer not to openly post it.
    Happy to pass it on via PM/email though.

    BTW nice to meet you at CTB, hope all the new gear is going great.

    Reuben.

  16. #16
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    Re: Second shot disaster

    Waiting four minutes between shots? I havent had to do this.

    If the machine has heated appropriately you should be able to make four - six double shots using the double basket.

    Although, I would say steam enough milk for two coffees at a time, do not try and steam a huge jug of milk.



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