Heat gun and thermos coffee roaster

No doubt this guy in this video made some awful, over-roasted charcoal, but the rig shows promise. I really like the use of the thermos as an insulated chamber. With some tuning of the heat control (thermocouple probe and variac for the coils maybe?) you could probably get this slowed down to a more reasonable six-to-eight minute roast before first crack.

10 thoughts on “Heat gun and thermos coffee roaster

  1. Alan Blue says:

    “you could probably get this slowed down to a more reasonable six-to-eight minute roast before first crack.”

    The part that amused me is that I was thinking “A piece of HVAC flexible ducting to recycle the hot air would make it -faster-.”

    1. John Park says:

      Haha! Slow down everybody!!

  2. Dave says:

    Simply putting a power rectifier diode in series with the heating coil would probably be enough for a “Low” setting.
    With a switch across the diode, the heat gun would retain its full original function.


  3. philliposophy says:

    It’s a good idea to heat and then cool the coffee as fast as possible. 1:50 is obviously way too long, but this was probably shown as a proof of concept: from green to charcoal in a minute 50.
    The thermos idea is great for heating quickly, but the cooling cycle should not take place in the same vessel. What cools hot coffee down _really_ fast is a few metal pans that’ve been in the freezer for a while.
    Done right, this person’s set up could be amazing.

  4. Rahere says:

    Connect the two tpgether and it’ll be starting to look more and more like a 12648430-cycle Stirling engine!

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John Edgar Park likes to make things and tell people about it. He builds project for Adafruit Industries. You can find him at jpixl.net and twitter/IG @johnedgarpark

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