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Thread: EM6910 Steam knob

  1. #1
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    EM6910 Steam knob

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Happy New Year everyone. I have just bought a Sunbeam EM6910 today. Generally from what Ive seen on the internet Im confident it will be a good machine, but Im unsure about one thing: I havent had a machine with a knob controlling the steam before. It seems that after turning the knob on half way, the steam begins, "full steam", so to speak - turning it further makes no difference, despite it being labelled "Max" at the end! Is this normally how a steam knob functions?

    Just after a little guidance :)

  2. #2
    Senior Member ozscott's Avatar
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    Re: EM6910 Steam knob

    Welcome to CS feZant and Happy New Year. What you have is normal. Just reduce the pump recovery time and increase the temp of the steam pump using the pump settings - and always then use full steam. It will produce very fine silky microfoam with practice and patience.

    Its a nice little machine that can produce coffee after coffee for the hordes...hop into it.

    Cheers

  3. #3
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    Re: EM6910 Steam knob

    Welcome to Coffee Snobs.

    Most of us recommend using full stem on any machine.
    Its one less variable to worry about.
    Trying to find the same spot on any steam knob (and I cant think of many machines with something other than a knob) is difficult.
    I know the 6910 has guide lines but really, for the amount of steam it puts out, you want all you can get.

  4. #4
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    Re: EM6910 Steam knob

    Welcome and happy New Year feZ. The steam isnt variable via the knob it is an on/off switch. So no matter how little or how much you turn it, the result will be constant.

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    Re: EM6910 Steam knob

    I beg to differ NE1.
    Its call a "Variable Steam Control Knob" (Instruction Book page 4).

    However, page 25 "Guide to milk texturing" says to "activate the steam function by turning
    the steam control dial clockwise as far as it will go", as I recommended previously.

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    Re: EM6910 Steam knob

    And remember to purge the wand for 10-15 sec first.... It makes a huge difference to the quality of the steam.

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    Re: EM6910 Steam knob

    I may be wrong... but MarcS posted it on this thread http://coffeesnobs.com.au/YaBB.pl?num=1190608338/3#3 and the two men who conducted the SB Sydney course seemed to think so also. I havent pulled it apart myself so i cant be sure though :-?

  8. #8
    Senior Member ozscott's Avatar
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    Re: EM6910 Steam knob

    I think - from memory (I just crank it up) - that when I first got it I worked out that on was on and off was off despite what it is called.

  9. #9
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    Re: EM6910 Steam knob

    I only quoted the book because I didnt have access to a machine at the time.
    This morning at work I tested it.
    It IS variable but not much.
    Theres on after about 2 lines, then about half way around you can notice a bit more steam, then fully rotated you can notice a bit more again.

    All up theres not much difference at all, it may as well be off/on.
    So much so that theres absolutely no way Id try to use it anywhere in between.
    Repeatability would be nigh on impossible.

    And as for Marcs thought on the other thread about the microswitch, I say its a safety switch.
    When the knob falls off the steam pump wont work.

  10. #10
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    Re: EM6910 Steam knob

    The switch activates the smaller steam pump. without it, no water would flow into the TB.
    (So it is a safety switch in sort as there is no water to build up pressure in the TB. If you pull off the knob and just press the switch (DONT try, some older machines do not have an OPV on the steam line!) it pumps water but no steam comes out, and either you hear it "squeal" like when it warms up, venting the excess pressure into the drip tray, or hear it go BANG and have to be paid a visit by the sunbeam pick up courier. (Like the older 6900 was prone to do)

    The valve is about as responsive as a T valve, with most of its limiting below where the contact meets the switch. After the switch is engaged, the valve can go between about 75 and 100%.

    No hard data just what I concluded after years of use and misuse of a few of these machines...


  11. #11
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    Re: EM6910 Steam knob

    My experience was (when the securing screw worked loose) that if I was in the middle of steaming with the 6900 and the knob fell off, the pump stopped, therefore no more steam.

    Your description of 75% to 100% sounds right from my experience but I dont fully understand your description.
    Surely if you take off the knob and activate the switch by hand it should steam UNLESS there is something else happening when you turn the spindle.


  12. #12
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    Re: EM6910 Steam knob

    i think there is 3 positions on the steam nob, off, sort of on, fully on. as said above you need it fully on.

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    Re: EM6910 Steam knob


    this steam valve works the same as an expobar leva or a bezzera bz99 and many others with a knob.
    internal thread with shaft screwing in and out letting pressure pass. (just like your taps in the house)

    with a boiler machine pressure is produced in the top part of the boiler, and in commercial type machines is fairly constant.

    the sunbeam uses a small thermoblock for steam,and a pump to push small amounts of water through it to generate steam.

    the switch turns on the pump to push the water into the boiler. if the switch doesnt work, or the alignment of the plastic body is incorrect then you wont get pressure.
    no pressure no steam

    if you turn the switch on by itself you will only increase the internal line pressure and risk blowing a pipe off or doing internal damage




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    Re: EM6910 Steam knob

    Quote Originally Posted by itsme5k link=1199101803/0#5 date=1199233076
    And remember to purge the wand for 10-15 sec first.... It makes a huge difference to the quality of the steam.
    So say a number of people, but for me, I see no difference between this and the steaming performance 10 - 15 seconds into the frothing of the milk. The machine doesnt know whether or not the nozzle is in the milk, and you havent saved any time overall, more likely wasted some.

    I just hold the nozzle a little above the milk, turn the steam on full, wait until the sputtering stops and then dip the nozzle in.

    When I get up to temp, I switch off the steam, which takes a few seconds to fully depressurise. I lift the nozzle out of the milk just before it finishes depressurising, thus ensuring that the nozzle stays clear and eliminating a separate purge after steaming. this takes a little practice, as if you take it out too early you make big bubbles and mess up the microfoam.

    The depressurising says something about the action of the steam knob. I have tended to think that its just a switch, not a valve. If I am right, then the source of steam for depressurisation is coming from residual steam pressure in the wand and residual water in the thermoblock that flashes to steam on cessation of water input. If I am wrong and it is a valve, then its just the residual steam pressure in the wand, caused by backpressure from the nozzle orifice.

    My work has an auto coffee machine with a steaming wand. when you switch the steam off (by pressing a button), it keeps steaming for a second or two and cuts off abruptly, no depressurisation. I put this down to a solenoid valve very close to the start of a short wand, so there is no volume to store steam.

  15. #15
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    Re: EM6910 Steam knob

    Quote Originally Posted by Meetim link=1199101803/0#13 date=1200287352
    Quote Originally Posted by itsme5k link=1199101803/0#5 date=1199233076
    And remember to purge the wand for 10-15 sec first.... It makes a huge difference to the quality of the steam.
    So say a number of people, but for me, I see no difference between this and the steaming performance 10 - 15 seconds into the frothing of the milk. *The machine doesnt know whether or not the nozzle is in the milk, and you havent saved any time overall, more likely wasted some.

    I just hold the nozzle a little above the milk, turn the steam on full, wait until the sputtering stops and then dip the nozzle in.

    When I get up to temp, I switch off the steam, which takes a few seconds to fully depressurise. *I lift the nozzle out of the milk just before it finishes depressurising, thus ensuring that the nozzle stays clear and eliminating a separate purge after steaming. this takes a little practice, as if you take it out too early you make big bubbles and mess up the microfoam.

    The depressurising says something about the action of the steam knob. *I have tended to think that its just a switch, not a valve. *If I am right, then the source of steam for depressurisation is coming from residual steam pressure in the wand and residual water in the thermoblock that flashes to steam on cessation of water input. *If I am wrong and it is a valve, then its just the residual steam pressure in the wand, caused by backpressure from the nozzle orifice.

    My work has an auto coffee machine with a steaming wand. when you switch the steam off (by pressing a button), it keeps steaming for a second or two and cuts off abruptly, no depressurisation. *I put this down to a solenoid valve very close to the start of a short wand, so there is no volume to store steam.
    Doesnt steaming without purging mean you get more water in your milk from the steam wand? Water is not a good thing from my understanding to go into milk that you are trying to get microfoam with. To each their own though.

  16. #16
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    Re: EM6910 Steam knob

    Quite a lot of water can come out of the 6910 wand before you get steam.
    I dont want it in my milk so always purge, turn the wand off, put it in the milk then turn back on.
    I also finish off the same way as Meetim but also give another half second purge as I wipe the wand clean.

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    Re: EM6910 Steam knob

    i tend 2 agree with brett. this is usually standard practice particurly for cafes, 10-15 secs a bit much for most machines (ie HX just a shot will do? like 1 sec), but for 6910 its quite wet so yeah for me 8 secs...

  18. #18
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    Re: EM6910 Steam knob

    This machine likes a good purge of about 20 seconds or so to really get cranking...do that and then stretch the milk and it performs very well.

    Cheers

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    Re: EM6910 Steam knob

    Quote Originally Posted by Brett link=1199101803/0#14 date=1200291310

    Doesnt steaming without purging mean you get more water in your milk from the steam wand? Water is not a good thing from my understanding to go into milk that you are trying to get microfoam with. To each their own though.

    When you see the small quantity of water that does go into the milk, I challenge anyone to prove it makes a difference. *you are talking less than 1ml of water (in my experience, anyway) in, say 250ml (worst case), in a product that is mostly water anyway. *Besides, what do you think happens to all the steam you inject into the milk? *it doesnt float away on the breeze, it recondenses into water. * This adds a small amount of water into your steamed milk. * I once started (but didnt finish) a calculation to determine what is the water volume of steam required to increase the temp of a given quantity of milk from 5degC to 60degC. Its actually quite tricky.

  20. #20
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    Re: EM6910 Steam knob

    Im more concerned with what could be in the water thats been sitting there for quite some time.

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    Re: EM6910 Steam knob

    the em69 series has a steam valve

  22. #22
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    Re: EM6910 Steam knob

    Quote Originally Posted by Meetim link=1199101803/15#18 date=1200633338
    I once started (but didnt finish) a calculation to determine what is the water volume of steam required to increase the temp of a given quantity of milk from 5degC to 60degC. Its actually quite tricky.
    Lets assume we want to take 100ml of milk from 5C too 60C. To do this will take 5500 calories (1cal per gram per degree C). At 1bar of pressure there is 639 calories of heat in each gram of steam. At the average temp of 32.5C there is 32.5 cal/gr of heat in the milk. Subtracting that from the total heat in the steam gives us 606.5 calories of energy available to heat the milk with. Dividing the 5,500 calories needed and dividing it by the 606.5 calories of heat available in each gram of steam tells us well need 9 grams of steam to do the job. These 9 grams of steam will be turned into water during the process there-by adding 9ml of water to the milk. Adding in heat loss to the container holding the milk, the higher density of milk over water, and rounding off of numbers etc and the amount of water added to the milk will be roughly 10% of the original volume of milk.

    While these are not precise numbers as theyre based on water rather than milk they should be pretty close. :)


    Java "I think I did that right!" phile

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    Re: EM6910 Steam knob

    Interesting. So going on meetims figure of 1ml of water exiting the steam wand during purge, that would turn 109ml of liquid into 110ml, and thus reduce the fat / protein content by about 0.9% of its previous value. If youre doing 150ml youre down to about 0.7%. Whichever way you look at it it doesnt sound overly significant to me. :-?

    I can imagine in a low volume commercial setup of the 90s (out of which many espresso mantras were carved) where the machine may have been sitting there unused for a while, you could get quite a volume of water condensing in a large steam wand so bleeding may have been done as a matter of course - but when were talking a short wand in a domestic situation maybe its not so much of a big deal? When I open the steam valve on the Silvia, its mainly warm air and sputters of water that comes out, neither of which are really going to help texture the milk so for me I think bleedings still a good idea; but perhaps its not the big deal its made out to be?

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    Re: EM6910 Steam knob

    Re the wand bleeding business, Ive created another thread for that at http://coffeesnobs.com.au/YaBB.pl?num=1203570795/



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