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Thread: How to alter temp on BFC jnr semi-auto

  1. #1
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    How to alter temp on BFC jnr semi-auto

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    I have just measured the temperature on my BFC semi-auto , thru the E-61 5mm inspection hole , and I have found it to be running a bit cool at 86.5* to 88* degrees.

    I would like to know how to turn up the boiler temp , without increasing the pressure beyond 1.1 bar.....

    Ive had a look inside but cant figure out if there is a separate controller for boiler temp.....


    This my machine




  2. #2
    Senior Member Dennis's Avatar
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    Re: How to alter temp on BFC jnr semi-auto

    Hi hotshod

    Some things to consider before turning up the temp...

    a) How long was the machine idle before you took those readings? I ask because the group will get hotter as time goes by - not exponentially, but hotter nonetheless.

    b) Does your coffee taste good? *If so, then this is a very good reason to leave it just the way it is.

    c) What prompted you to take these readings? *If it was just for something to do, then resist the urge to fix something that aint broken.

    d) The readings you have taken at the hex bolt will be different to the water temp as it hits the puck

    92 degrees is far from the be all and end all. *I run a commercial 2 group at 89, because:

    1) The coffees I use taste better to me at that setting, and

    2) Ive tried different settings (higher and lower), different water flow rates, different coffees, different grind settings, under and overdosed, and it still tastes best at 89.

    Hopefully that may put your mind at ease, unless of course, your coffee tastes sour.


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    Re: How to alter temp on BFC jnr semi-auto

    Hi Denis
    Thanks for your prompt reply.

    I took the temps because I was detecting sourness in my espressos...... hard to tell in milk based drinks , but definitely in the espressos .

    My temps were taken after 2 hrs , and if I do 2 or 3 pour in a row the temp was down to 84*.

    I had the pressure stat kicking in at 0.98 bar and off at 1.05 bar ( approx , according to gauge).....
    This has been lifted to 1.05 and off at 1.12... and it is a bit hotter , just under 89*.

    So how does one wind up the temp without increasing pressure???

    Thanks
    hotshod

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    Re: How to alter temp on BFC jnr semi-auto

    Quote Originally Posted by 3433282F3433385C0 link=1277896081/2#2 date=1277902235
    So how does one wind up the temp without increasing pressure???
    Hmm...I wonder if something (scale) is restricting flow through the thermosyphon? Might be worth looking for scale in the group and also in the thermosiphon. Id check the gicleur at the same time- just to be sure.

    The Junior Semi should not be running cold and not withstanding a dodgy gauge and or pressurestat, the only practical way of running it hotter is to bump up pressure unless youre into boiler production and HX design and have the equipment to fabricate your own bits.

    Id check pressure at the group as you can get sourness with low extraction pressures. I saw it recently in a VBM DS where the owner had dropped to a little under 9 bar on the gauge- which was actually not much more than 7 bar for his machine...

    Chris

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    Re: How to alter temp on BFC jnr semi-auto

    Thanks for the info Chris...

    It is about 10 months since I did a descale *so I guess it wouldnt hurt to do again.

    All my info is coming off the installed gauge. I measured temps this morning after 2 1/2 hr warm up with the increased pressure ( as above ) and it came in at 91.7* *on first flush , over the next 15 min I did 2 more readings and it was down to 89.5*...... I guess , this puts in an acceptable range.

    Would you advise to do a descale , then apply a Scarce device to check?

    Cheers
    Greg
    hotshod @ CS

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    Re: How to alter temp on BFC jnr semi-auto

    Quote Originally Posted by 484F5453484F44200 link=1277896081/4#4 date=1277943190
    Would you advise to do a descale , then apply a Scarce device to check?
    Absolutely Greg ;)

    Chris

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    Re: How to alter temp on BFC jnr semi-auto

    Hi Greg,
    Are you using an Eric Svendson-type device to measure the temperature from the e-61 inspection hole?

    Have you checked the accuracy of this device against that of boiling water? ie. does it indicate 100C when put in boiling water? It could be a few degrees out..

    Cheers,
    Paolo

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    Re: How to alter temp on BFC jnr semi-auto

    Just a thought Greg...

    I assume you have confirmed that the issue is definitely with your machine and not with your coffee or the way you are pulling shots? Youve cupped it for no issues and can pull a good shot on another mahcine with it? :-?

    I reckon we too often blame our tools... ;)

    Also, I have a theory that Scace devices read a tad cool and maybe shooting for 95 or so oC is where we really need to be...

    Chris

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    Senior Member Dennis's Avatar
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    Re: How to alter temp on BFC jnr semi-auto

    Hi again Hotshod

    By all means descale/scace your machine.

    While the temp drop may have occurred suddenly, it could also have happened gradually, or in fact may have always been the same.

    I note that youre a home roaster and understand that home roasters dont like to hear the following, but Ill ask anyway. *Is there ANY possibility that your roast may be at fault?

    EDIT: I had a laugh Chris...great minds... ;D



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