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Thread: Shot timing

  1. #1
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    Shot timing

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

    How do you time a shot correctly? I have an Isomac Tea and am using a VST 18g basket to make two 30ml espresso shots.

    Should I start timing as soon as I activate the brew lever, or once the coffee starts to flow from the portafilter spout?

    Does the pre-infusion time get counted in the 30ml in 30 second rule?

    Cheers

    Sam

  2. #2
    Senior Member Barry O'Speedwagon's Avatar
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    You can obviously do whatever you like, but for the purpose of a standard, most times that you see people referring to are from when you pull the brew lever, to when you cut the shot. That's basically the length of the 'brewing' process (i.e. the time for which the grinds are in contact with the hot water under pressure).

    What exactly do you mean by 'pre-infusion'? Do you mean the delay between pulling the lever and the first drops? Or a manual pre-infusion without pressure?
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    I thought that would be the answer. Thanks

    I was referring to the delay between pulling the lever and the first drops, but now you mention it, I have seen some E61s operated by activating the lever half way for a few seconds to wet the grinds, and then all the way for full pressure. Does that have any merit do you think?

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    Senior Member Barry O'Speedwagon's Avatar
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    Quote Originally Posted by SamSan View Post
    I thought that would be the answer. Thanks

    I was referring to the delay between pulling the lever and the first drops, but now you mention it, I have seen some E61s operated by activating the lever half way for a few seconds to wet the grinds, and then all the way for full pressure. Does that have any merit do you think?
    My (e61) machine is not designed to do the 'pre-infusion' thing, so I'm not in a position to comment. I'm sure heaps of others will
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    Thanks anyway, mine isn't either. I guess I was wondering if activating the lever half way for a few second would be beneficial on a machine not designed for pre infusion.

  6. #6
    Senior Member Barry O'Speedwagon's Avatar
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    Dunno, but I suggest that isn't ideal for your machine.

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    Senior Member artman's Avatar
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    That only works if machine is plumbed in where halfway opens the water path under mains pressure without activating the pump.

    Even without plumbing in the E61 group has built in pre infusion by way of the hydraulic design. That's my understanding.

    Cheers

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    Quote Originally Posted by Barry O'Speedwagon View Post
    (e61) machine is not designed to do the 'pre-infusion' thing
    ...sounds like an oxymoron, the e61 was designed specifically to perform pre-infusion ???
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    Righto, I guess there is no benefit in my case for opening the lever half way as my machine is not plumbed in.

    Cheers

  10. #10
    Senior Member Barry O'Speedwagon's Avatar
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    Quote Originally Posted by ArtW View Post
    ...sounds like an oxymoron, the e61 was designed specifically to perform pre-infusion ???
    Fair point. But my Diadema Reale in not plumbed in, and the bloke who sold it to me (a regular on here) advises against doing it. Surely whether you get any water flow from the halfway position depends on how the lever microswitch is set?

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    Senior Member artman's Avatar
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    Doesn't the pre infusion work automatically by simply moving the lever from off to on? ie no need to stop halfway. Obviously if plumbed in you can extend the pre infusion by doing the halfway thing.

    Cheers

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    There is two types of pre infusion on an E61 tank machine. First is the "Halfway position" due to the heat exchanger there is a natural flow from the HX siphoning that will come thru the group which is enough to wet the puck and begin (Try find the halfway point on your machine before locking your handle in).

    The second people talk about is the slow build up of pressure from the Vibratory pump, it take about 5 seconds roughly to get up to full 9 bar so before it gets there you have a gradual ramp of flow rate and pressure as the pump gets up to its desired setting. Hence, the pump is giving you an unintended pre infusion.

    With a plumbed in machine that runs a rotary pump, the line pressure is going push thru the HX or Dual boiler with the halfway lever position at around 3 bar depending on your household mains pressure. When the pump is activated there is almost no pressure ramp because the pump is driven by a motor that is virtually at full speed once engaged. Hence, no pre infusion. (Unless you open use the halfway lever method)

  13. #13
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    Hi SamSan,

    I wouldn't worry about preinfusion. All e-61 machines have inbuilt preinfusion as it is designed in the group.

    Lifting the lever slightly in the hope of opening a piston to partially empty the HX? I'd love a double blind on that one as I suspect there is a hefty dose of placebo effect in what is reported. There may also be an effect on shot temperature by doing this as the HX will empty partially.

    As for shot timing, the bottom line is that once your shot starts to blonde, you have extracted the maximum possible yield from the dose you have used. Many choose to use less and a little experimentation will show you that the overwhelming body of the shot is in the early pour.

    Settle on a dose that works for your setup and do whatever you need to do to keep the dose rock solid consistent so that the primary (only) variable is grind size. Some use a scale- I don't.

    Experiment with timing- A fast shot will normally be sour and a slow shot bitter. Somewhere in the middle a wonderful balance exists and that's what you're chasing. The "rule book" would suggest roughly 25ml in 25 sec from the appearance of the first drop, but that is merely a starting point. Once you have consistent technique, you will learn to bend the rules according to your palate and the shot chemistry your desire.

    It's a wonderful thing espresso. You never stop learning!

    Cheers

    Chris
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    Quote Originally Posted by brendogs View Post
    There is two types of preinfusion on an E61 tank machine. First is the "Halfway position" due to the heat exchanger there is a natural flow from the HX siphoning that will come thru the group which is enough to wet the puck and begin (Try find the halfway point on your machine before locking your handle in).

    The second people talk about is the slow build up of pressure from the Vibratory pump, it take about 5 seconds roughly to get up to full 9 bar so before it gets there you have a gradual ramp of flow rate and pressure as the pump gets up to its desired setting. Hence, the pump is giving you an unintended pre infusion.

    With a plumbed in machine that runs a rotary pump, the line pressure is going push thru the HX or Dual boiler with the halfway lever position at around 3 bar depending on your household mains pressure. When the pump is activated there is almost no pressure ramp because the pump is driven by a motor that is virtually at full speed once engaged. Hence, no pre infusion. (Unless you open use the halfway lever method)
    Quite a bit of miss information there ..!
    artW was spot on in that the E61 was designed with controlled pre infusion built in no matter what type of pump is used.
    there is a low pressure relief valve that operated for the first few seconds and works in conjunction with the "gicular" ( jet) to ensure only low pressure brew water is flowed onto the puck until the lower group chamber is filled, then the full pump pressure is directed to the puck.( that's what the valves in the lower chamber are for, any why the pump appears to take a few seconds to get up to pressure )
    With a plumbed in machine, (and IF the valve settings are suitable, because some groups won't function like this) ....then the " mid position" of the lever before the pump is activated, can be used to direct mains pressure water to the puck for a PI effect for as long as desired.
    ( note:-depending on the spring tension settings, there may also still be the in built preinfusion period after the " manual" action)
    it is not wise to use the "no pump" mid position PI method on a tank machine, because the pressure in the HX that pushes the brew water onto the puck, is caused by forming a steam pocket in the HX which can cause spluttering buring brewing and possibly disturb the puck.
    Another "faux" PI technique is of course to simply fully lift the lever for a few seconds to activate the pump and inbuilt PI period,..but before any coffee drips start (2-4 secs) put the lever back to mid position ( NOT fully down) for an extended PI time..this tends to prevent the steam bubble forming as there is no further low pressure flow once the puck is wet.
    you can make your own assessment of the benefits or otherwise of different PI methods with the E61, but if the group is set and maintained normally, there will always be some PI period in operation.

    But, back to the original question of shot timing..
    if you are just using the machine without any extra manual PI , time from the moment the pump starts.
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    Quote Originally Posted by blend52 View Post
    Quite a bit of miss information there ..!
    I think that was a tad harsh blend52.

    You have nailed the e61 design for pre-infusion. I don't deny what you're saying. I was trying to give another dimension to the discussion and yes the pumps are a huge factor. It was obvious they were talking about extending the pre-infusion time by using the halfway lever technique. When I have my Scace hooked up to my Expobar Minore (Rotary pump version) the initial in built pre infusion only last 1 - 1.5 seconds before full pressure is realised, this time will also be increased or reduced by the amount of clearance from the puck to the shower screen. You will find this number substantially increases with a Vibration pump before full pressure is realised. When I tested it on my Vibiemme Domobar Super which is a tank version and Vibratory pump, full pressure isn't realised up to 10 seconds! This figure will change with the age of the pump and amount of use.

    So are the pumps a factor? Yes, they are.

    The guys were talking about extending that Pre Infusion time with the halfway lever trick, so I thought it may be important for them to understand the differences from another perspective.

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    Sorry, brendogs, I didn't mean it to be harsh.
    .pumps can be a factor, but that is more due to the flow capacity than the actual type of pump.
    Most of the vibe pumps seem to have less than half the flow rate compared to the rotarys, and some manufacturers fit different size gicleurs which also alter flow rate.
    ..so yes the PI time can vary considerably depending on the specific build set up.
    i guess the rotary pumps were originally sized to supply multi group commercial machines ?
    Most important fact to me is that if a E61 group is assembled as originally intended, with a "dwell" at the mid point on lever movement , both the drain valve AND the inlet valve remain closed , and no PI flow can occur.
    However , many groups have assembly tolerances that result in no clear dwell at the mid point and then line pressure PI can be used...sometimes needing the lever to be slightly lifted to open the inlet valve.

  17. #17
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    Thanks everyone for the clarification regarding pre-infusion. My machine takes a good few seconds to get to full brew pressure (according to the gauge), so by the sounds of it, I am getting plenty of pre-infusion by default considering the vibe pump and E61 design. Initially I was wondering whether to include this time or not in my "general rule" as it is a significant portion of the total 30 seconds.

    As for shot timing, the bottom line is that once your shot starts to blonde, you have extracted the maximum possible yield from the dose you have used
    Once you have consistent technique, you will learn to bend the rules according to your palate and the shot chemistry your desire
    I think Chris has really hit the nail here with these comments. I should probably be focusing more on the early signs of blonding rather than the actual shot time. And to trust my palate, and experiment to find the perfect balance for my taste.

    I have settled on a pretty consistent dose technique, and am probably pretty close to the "general rule" anyway. I'm not that familiar with recognising blonding so that's something I'll have to look into.


    Cheers

    Sam

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    Looking to get some opinions on what to change to combat early blonding, or even some feedback on the video below on when blonding occurs?
    I did some beginner training at a local place in Perth last year, some of it was helpful but a lot of it was filler material to hand out certificates for cafe employees to be honest - spent a few seconds on blonding and we weren't using naked PF's. To me blonding is at about the 24-25 second mark? I would normally cut it off at around 27sec. Taste was ok but I've fluked much better with the same blend before.

    First drops weren't until 8-10 seconds in but if I grind any coarser blonding is even earlier and the sourness kicks in. Any suggestions? Thinking I may bring out the 20g VST basket to see if the higher dose helps..

    Setup in clip:
    - 17.5g in 17g LM basket
    - Approx 1:1.5 (25-26 grams out), i'de like to get this closer to 1:2
    - Equipment definitely isn't to blame
    - ONA blend 8 days post roast



    Result:
    IMG_3405 (1).jpg



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