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Thread: timing extraction? manual pre-infusion technique?

  1. #1
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    Red face timing extraction? manual pre-infusion technique?

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Hello everyone

    regarding the old advice of ~50-60 ml of double espresso extracted in ~30 seconds for a great double-shot quality.

    Two questions:

    (1) When do you start the timer for 30 seconds - from the instant the first drip of coffee appears out of the filter basket/spout or from the instant when you flick the switch to start the water pour/extraction?

    (2) Does the manual pre-infusion change anything?

    I have Rancilio Silvia 2010 model and I tried manual pre-infusion a few times (flick the pour button for 2-3 sec, stop pour button for 2-3 sec, flick the pour button for 30 sec) and the result was no better than not doing pre-infusion manually at all, i.e. just flick the pour button for 30 seconds.

    Perhaps I am doing manual pre-infusion wrong or perhaps on this kind of home machine it makes no difference (a waste of time and effort) or perhaps I am not timing it correctly.

    Thanks for advice and opinions on (1) and (2) above.
    ACID drinker

  2. #2
    Senior Member Yelta's Avatar
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    Morning AR, I have always started timing from the moment I hit the brew switch.

    Re preinfusion, I used a Silvia for many years, tried the manual preinfusion route, in my opinion it made no discernible difference.

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    Acid_Rider, brewing is the time in which the ground coffee is in contact with the hot water. So, from the second you hit the switch start timing.

    Pre-infusion works best on on the old hand operated lever machines where control of water pressure is feasible.

    With semi-automatics, you hope to switch on/off quickly before the pump ramps up to full pressure of 9 bar so the puck is not blasted.

    The problem is, as soon as you switch off after a couple of seconds, the 3-way valve opens. I don't know whether that is a desirable thing to happen before the extraction completes.

    My machine with metered dose does that...switches on, monetarily off, 3-way valve opens, ramp up again to completion.

    I suppose I could bypass the touchpads and use the manual switch and see whether there is any appreciable difference. Even if there is, I would lose the most welcome convenience of the self-timed process.

  4. #4
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    Re timing. As stated by others, start soon as you flick the brew button on. For good coffee...dont rely on that. It is just a way of you working out if you are *in the ballpark* wrt actually making an espresso brew and having your grind / dose / tamp somewhere within coee of correct settings & technique. You can then vary your grind dose tamp / timing, to see what suits your current bean supply and your taste buds better.

    Re so called "manual pre infusion". Unfortunately this is one of those web / forum perpetrated fictions and is very much dependent on the type of machine you are using.

    On a Silvia....forget it. What you are actually doing is making the coffee worse...because every time you flick off the brew button, you activate the exhaust cycle which takes that bit of infusion that just went into the puk, and then dump it into the drip tray...so you just removed the infusion. Then you start the button / infusion again, and the resulting brew in your cup is missing that first bit of the brew that was dumped out.

    Perhaps the above is not clearly explained, so let me explain real pre infusion and you will understand:
    On a machine that does have electric pre infusion programmed, it starts then stops the pump from pumping more water into the puk, BUT IT DOES NOT OPEN THE EXHAUST PORT. Ergo the first infusion stays in the puk to infuse more oils, before the pump restarts to send the whole lot through into the cup. With your machine there is no way of stopping the exhaust port opening when you switch off the pump...so you are infusing, then dumpiing, then restarting. No future in that.

    Just flick the button on, make coffee, and flick off at end. In the hands of a good operator, Silvia makes excellent coffee as is.

    Hope that helps.

    Attilio
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    CafeLotta likes this.

  5. #5
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    Many thanks to everyone who replied.
    I am glad I gave up on manual pre-infusion on Silvia as I did not get good results there.
    I do the stop-watch timing from instant I flick-ON-switch, and it looks like this is the correct way to do it.
    I also practice temperature surfing on Rancilio Silvia:
    I flick ON the pour switch, the heating light comes on a few seconds later, I stop the pour.
    I then wait for the heating light to go OFF and only then I then press the pour button, timing for ~30 seconds for ~50-60 ml for a double shot.
    Cheers everyone.
    Last edited by acid_rider; 22nd March 2013 at 03:38 PM. Reason: spelling errors

  6. #6
    Senior Member mwcalder05's Avatar
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    Call me all you want, but I've never timed my shots at home and I believe on pulling the shot as soon as it is finished (when it turnes to a certain colour). But most of all I like my taste buds to determine how good a shot is, not a timer. Unfortunately, I'm stuck with pre-infusion with my Sunbeam 6910 so I can't testify as to which is better. If I was to time, I would start the clock as soon as the brew button is pressed.

    Michael

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    Atillo, my Grimac 2-grouper has electronic preinfusion. But it does call into play the 3 -way valve.

    When I press the touchpad, a few drops of water---just a few--are pumped through the shower screen before the valve opens and a decent stram of water exhausts into the drip tray. The amount of spent water is much greater than what exited the shower screen. And it emerges clean, no coffee.

    Then the pump ramps up again to complete the cycle.

    As I say, I should bypass the touchpads and use the emergency manual switch to see if it makes a difference.

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    Quote Originally Posted by Fresh_Coffee View Post
    Perhaps the above is not clearly explained, so let me explain real pre infusion and you will understand:
    On a machine that does have electric pre infusion programmed, it starts then stops the pump from pumping more water into the puk, BUT IT DOES NOT OPEN THE EXHAUST PORT. Ergo the first infusion stays in the puk to infuse more oils, before the pump restarts to send the whole lot through into the cup. With your machine there is no way of stopping the exhaust port opening when you switch off the pump...so you are infusing, then dumpiing, then restarting. No future in that.
    Does that mean that if I modify the wiring to the 3-way solenoid, I can get real preinfusion to work?

    What about keeping the steam valve open at the start, then gradually closing?

  9. #9
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    NO....

    a) rewiring the electrovalve WITHOUT HAVING SOME KIND OF CONTROLLER in play to switch the correct functions during the cycle will do nothing (except maybe stop it working in toto) and

    b)DONT TOUCH ELECTRICAL WIRING IN YOUR COFFEE MACHINE WHETHER ITS UNPLUGGED OR NOT.

    c) dont fix things that aint broke. There is absolutely nothing wrong with non preinfused coffee....and wrt what is said in a lot of these esteemed forums, there is no doubt in my mind that any significant difference anyone can find between pre infused and non pre infused coffees when made with same operator, beans and equipment, could well be all in the mind, instead of in the taste buds. Pre infusion is not coffee nirvana.....its just another management function offered whereby individual machine operators may choose to, or choose not, to use, if the individual thinks it will, or wont, help his coffee......

    Hope that helps.

  10. #10
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    Quote Originally Posted by Fresh_Coffee View Post

    c) dont fix things that aint broke. There is absolutely nothing wrong with non preinfused coffee....and wrt what is said in a lot of these esteemed forums, there is no doubt in my mind that any significant difference anyone can find between pre infused and non pre infused coffees when made with same operator, beans and equipment, could well be all in the mind, instead of in the taste buds. Pre infusion is not coffee nirvana.....its just another management function offered whereby individual machine operators may choose to, or choose not, to use, if the individual thinks it will, or wont, help his coffee......

    Hope that helps.
    Iv'e played around with different pre-infusion methods on Silvia and I agree that I wasn't able to find one that benefited the coffee. Pulsing the button or having the steam wand open just added more difficulty without any obvious differences in the cup. But to say that Pre-infusion is just internet hype?

    It depends on how the pre-infusion is implemented. On higher end machines Slayer/Strada/Hydra it completely changes everything. An 8-10 second 2-4 bar pre-infusion facilitates the use of a much, much finer grind. It changes the way fines migrate through the puck (no more fast/slow/fast espresso pours) It serves to round off the acidity in brighter coffees and improves body, it facilitates the use of lighter roasts and larger doses. It's another tool which I have found improves the taste of most coffees.

    On a silvia its going to be very hard to replicate this, the only way I can think would be to use some kind of voltage controller on the pump and have a pressure gauge also installed to tell you whats going on. This is just theory though. It probably wouldn't work to make the coffee better.

    The machines I've mentioned above have had a lot of R+D put into them and come as a complete package where everything is working together + some secret sauce that is beyond my understanding, adding pre-infusion to a Silvia by electronic overrides is unlikely to give you the same results.

    If pre-infusion was all just voodoo and internet gossip we would all just be using GB5's. From a baristas point of view, manual pre-infusion slows you down, it makes channeling (when it happens) much worse, its another parameter to try and juggle, it requires us to drink more espresso when we probably already have enough.

    Regardless of all this, Silvia makes great coffee. Use good coffee, a good grinder and good technique and you will get espresso that tastes great. If your coffee doesn't taste good with a Silvia you need to change how and what your brewing not the machine your brewing it on.

    Just for background, I use a Silvia + Mazzer Super Jolly at home that I have owned for over 6 years. At work I make over 200 coffees a day on a La Marzocco Strada previously on a Linea. I know the difference and there is a hell of a lot more to it than internet hype.
    Last edited by muppet_man67; 23rd March 2013 at 12:42 PM.

  11. #11
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    In my Breville Dual Boiler the shot clock starts when I press the button and the time includes the preinfusion. I expect other machines with shot clocks would be similar. The three way valve does not activate during preinfusion.

    Barry

  12. #12
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    Quote Originally Posted by Fresh_Coffee View Post
    NO....
    a) rewiring the electrovalve WITHOUT HAVING SOME KIND OF CONTROLLER in play to switch the correct functions during the cycle will do nothing (except maybe stop it working in toto) and
    b)DONT TOUCH ELECTRICAL WIRING IN YOUR COFFEE MACHINE WHETHER ITS UNPLUGGED OR NOT.
    c) dont fix things that aint broke. There is absolutely nothing wrong with non preinfused coffee....and wrt what is said in a lot of these esteemed forums, there is no doubt in my mind that any significant difference anyone can find between pre infused and non pre infused coffees when made with same operator, beans and equipment, could well be all in the mind, instead of in the taste buds. Pre infusion is not coffee nirvana.....its just another management function offered whereby individual machine operators may choose to, or choose not, to use, if the individual thinks it will, or wont, help his coffee......
    How do I install a PID without violating point b?

    as for modifying the wiring, I was going to wire it to the hot water switch (which I don't use) to open the 3-way - so I hit both switches to start, turn off the brew switch to allow it to preinfuse, then turn it back on to actually brew.

    (ie wire brew switch to just run the pump, and hot water switch to open the solenoid. of course, this makes it impossible for anyone other than me to use the machine, but I can live with that.)

  13. #13
    Senior Member askthecoffeeguy's Avatar
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    Behmor Brazen - $249 - Free Freight
    I'd also like to add that everyone has their own personal preferences when it comes to extraction times and volumes - personally I prefer not to run any extraction past the 45 to 50ml mark maximum - and even then I'd be looking for a longer extraction time than 30 seconds - to my mind at least 30ml from 30 sec is a good ratio to aim for - but it also depends on the machine and the setup and the size of the baskets that you're using etc...

    ACg



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