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Thread: HX Q & A

  1. #1
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    HX Q & A

    Gene Cafe Coffee Roaster $850 - Free Beans Free Freight
    Having only recently started using a machine with a Heat Exchanger Im still getting used to the idiosyncrasies that come with it. At first I thought my Diadema was running a bit hot. I had the boiler set between 1 and 1.1 bar so I drop the pressure down to 0.8 bar but the steaming power was ordinary and I still had to flush what I thought was a lot of water.
    Current status is:
    Cycling between 0.9 and 1.0 bar
    I need to flush approx 240ml to get brew water temperature down to 95*C but I wouldnt mind if the brew water was closer to 93*C
    Im measuring the brew water temperature using a K-type thermocouple shoved up the spout of the portafilter if this no good please tell me *:)
    I guess my concern is that Im having to flush too much water and or if I dont flush heaps of water Ill burn the coffee resulting in bitter brew...
    Please flood me with information and advice. It might be that Im just new to the world of HXs and what it takes to achieve appropriate brew temperatures. I may well be overanalysing things as the coffee produced tastes very good but if there are some experienced HX users out there with tips Id like to hear them.
    Ive read http://www.home-barista.com/hx-love.html and it helped a lot.

  2. #2
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    Re: E61 Q & A

    I havent touched the pressure on my machine nor tested the temperature. The gauge shows around 1.1 bars and the coffee doesnt taste too hot after flushing a couple of hundred mls of water before each round of pours.

    Bear in mind that you are using a small commercial class machine and if you are not producing a steady rate of coffee through the day it will be too hot after being left alone for a while since the machine is designed to maintain a good temperature profile while producing cup after cup.

    Cheers

  3. #3
    Super Moderator Javaphile's Avatar
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    Re: E61 Q & A

    Quote Originally Posted by Wired link=1115801103/0#1 date=1115866513
    Bear in mind that you are using a small commercial class machine and if you are not producing a steady rate of coffee through the day it will be too hot after being left alone for a while since the machine is designed to maintain a good temperature profile while producing cup after cup.

    Cheers
    This is true of just about every HX machine, small or large. :)

    Java "Flushes are a way of life" phile

  4. #4
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    Re: E61 Q & A

    I had an email convo with Sharkboy about this topic, and I anecdotally responded. Ive put the white lab coat on and pulled out the Highly Accurate Measuring Device(tm) and now can conclusively say that.... when making two coffees at once, with 30+ mins warmup time....

    my initial flush is ~125ml
    my second flush is ~80ml

    A third coffee about 3 mins later still only needs ~80ml.

    HAMD(tm) = pyrex measuring jug.

    No thermocouples were harmed in the collection of these statistics

  5. #5
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    Re: E61 Q & A

    Poundy, Wired, Java

    Thanks for the input guys. If possible can you measure the temperature of the water at the spout and note the volume of water flushed.
    Im using a cheap DMM with a K-type thermocouple.
    Im trying to become less empirical about the whole coffee making process and atm am just watching and listening for the water to stop spluttering and then pull the shot.
    Must resist analysis...

    Ill have to organise a Newcastle CoffeeSnobs get together and do some comparison tasting.


    Stephen


  6. #6
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    Re: HX Q & A

    OK, perhaps over the weekend I too will grab my Jaycar cheap DMM plus thermocouple (24.95, who could ask for more ! Oh except for leaving it in the sun and having one segment in the "tens" digit giving out ;))

    Yes, please do. Saturday July 16th would be good. Im intending to be at a mountain bike orienteering race in Cessnock on Sunday ;D

    Ill return the favour with an Oberon open house, where the price of entry will be a kilo of green beans - to throw in the roaster, of course!

  7. #7
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    Re: HX Q & A

    Sorry but I dont do metric.

    I get the water temperature about right by flushing, I adjust grind by eye, I fill the basket by eye, I tamp by habit, pour by eye, and drink by mouth.

    I consider coffee an art more than science. 8)

    Cheers

  8. #8
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    Re: HX Q & A

    Behmor Brazen - $249 - Free Freight
    Sharkboy,

    I left my Diadema the way FC set it - 1.1-1.2 on the gauge and ran the old -

    Im trying to become less empirical about the whole coffee making process and atm am just watching and listening for the water to stop spluttering and then pull the shot.
    I get mixed results, but similar to yourself, I have only had my machine for about 1 month and still learning! ::)

    Interesting to hear that you are flushing around 240ml....I flush into 2 shot glasses which is a round 180ml and then I fill the basket, tamp and set my timer before flushing once again. The portafilter goes in and we all know the rest from here.

    Seems as though I am pretty close to the mark temp wise (without verifying with a Thermometer) but I think my problem is that after pouring the first shots, I then have a break of around 5 mins whilst I do milk etc and come time to brew again, I am using the same technique (2 glass flush..)

    I understand the purpose of flushing is to reduce the temperature of water, but perhaps I am flushing too much and that may explain why my second round of shots pour differently (Sometimes too quick and others too slow) compared to the initial run. ???

    Perhaps I need to invest in a digital thermometer.....

    Ciao`

    James



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