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Hottop specs - recent changes

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  • Hottop specs - recent changes

    Hi all,

    There've been a few notable changes to the Hottop KN-8828 series roasters over the last year and from some questions we've had it seems some people aren't aware of these recent changes.

    Those who've been around a while will know the KN-8828 series as a 250-300g electric drum roaster with an external cooling tray. The B model gives full manual control of heater power and fan speed much the same as a commercial roaster while the P model is more automatic if that's your thing.

    The version 2 units (e.g. KN-8828B-2) have been out for a little while now. Some people have been confused over this - operationally they are IDENTICAL to the version 1 units. The only external difference is the addition of a manual eject mechanism so in the event of a power failure you can still get the beans out without burning yourself. So if you have a v1 unit there's no particular need to change it for a v2 unless the power in your house has a habit of tripping! There are some internal improvements that make it nicer to work on but these don't affect operation. Externally this is identified by the gold knob under the rear fan.

    The most recent change is the addition of a K-type 'bean mass' thermocouple, as denoted by the K in the part number suffix (e.g. KN-8828B-2K). This is something we've lobbied Hottop for for a long time so were pleased to see it!

    Unfortunately as you can see, it's positioned a bit high, especially if you're loading around 200g, and isn't as accurate for measuring bean temperature as our bean mass probe / datalogger retrofit which sits lower down. It can't be connected to a PC either but that's nothing out of the ordinary for a factory solution. In the graphs below the blue line is our retrofitted bean mass probe. The red line on the left graph is the old built-in sensor which the dotted line on the right graph is the new factory probe.

    Given the choice between the two the new probe is definitely an improvement over the old. While the absolute reading is a fair way from reality near the end of the roast, it still follows roughly the same shape as the actual bean temperature; whereas the old sensor, while closer in absolute numbers at the end of the roast, doesn't represent as well the rate of change of bean mass temperature at that critical stage of the roast.

    The only other change Hottop have finally implemented for us came with the K models, and it's a red eject button on the B control panel! That's the sort of thing that should have been there from day one, and it might seem like a little thing; but any Hottop user will tell you how easy it is to accidentally bump the eject button when going for one of the others. At least now that's a bit harder to do!

    Click image for larger version

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    So that's where things are currently at! Hope this helps to clarify a few things; there are normally a few Hottop users lurking around CS and I'm sure they'd be happy to answer your questions. Otherwise have a browse through (see if you can spot Habib's mugshot! )


  • #2
    The eject button upset me many times!
    The most useful mod, apart from setting the thermocouple myself (using a drill and with teeth grinding pre-pullman mod) which is a necessity, was taping a clothing button(from above) over the eject button - so you have to lift the button to intentionally eject. Brilliant!


    • #3
      I'd agree so this is a welcome improvement! How do you find your thermocouple readings vs your built-in one? Assuming you have a fairly early B model, must have done plenty of roasts by now?!


      • #4
        The difference I found was similar to the hottop(nonpullman) one and the probe was similarly positioned.

        Most of my learning was done by manually logging the temps on paper so I got a good feel for how the temps varied at different stages of the roast and how the settings varied that, and was able to repeat roasts to within 1 degree or about 20sec.
        Must have done >120kg before upgrading to a bigger roaster. Here the behaviours are much the same (also electric) but responses to changes are slower to occur so I place less emphasis on env temp after dropping the beans into the roaster. The CS roastmonitor software helps these planning changes heaps but now I just follow the bean temp with a good idea of the roasters kinetics.
        Got the Hottop out again after 18months to play and it felt like getting back on a bmx bike! Thinking 2 temps again also made my realise how things had changed in my mind.
        Glad I kept it.