Identify this graph

A little bit of fun.  All you have to do is identify what this graph is charting out.  The x and y scales are linear.  It has something to do with coffee.  The first person to identify it will get a bag of tasty, tasty coffee sent to them from me.  Terms and conditions apply 1

Also – please leave a comment to guess so other people can see. Submissions won’t be accepted via twitter etc.


Clearly I’ve made this too tough.  Here is the same graph with a little more information on the axes:

  1. Well – no one at Square Mile Coffee can enter nor frankly needs to – the prize wouldn’t be very interesting, nor can Ben Kaminsky.  ↩︎


  1. Desire to drink coffee vs time of day

  2. It’s a flipped over Roasting S-Curve…

  3. Sales of Starbucks since the introduction of New RedBrick
    (probably not but it’s worth a shot)

  4. The temp. curve while flushing a hx espressomaschine

  5. it does remind me of the temp loss curve of a v60, 

    might also be amount of sleep in proportion to the lenght of barista career.

  6. but if the X-axis is in seconds & Y-axis is in degrees it would be too fast?  Unless it is a really small home machine?

  7. Exactly.  I have @ home a Rancilio L7 with a small hx and a temp. control in the group. The temp curve while flushing is here nearly the same… But honestly I guess Mr. Hoffmann means something different ;)

  8. Rate at which the beans degas after being roasted?

  9. That looks like the effect of roasting on an acid- lactic? Malic? I’d need to look at my notes!

  10. Amount of pressure exerted using a lever operated espresso machine?

  11. A completely random chart of coffee information on arbitrary axes?

  12. the number of hits on this website from the start of your sabbatical up until the first post 2012.

  13. is “something related to roasting” enough?
    development of vegetal flavour-components during roast (even though I don’t think that can be messured in a 3-30 scale). hmmm…

  14. Coffee roasting moisture content in some way?

  15. Amount of crema produced vs the time the coffee is left to brew?

  16. The aroma amounts in the gorunds starting from fresh grind and decreasing over the next 15 minutes or so.

  17. 9 minutes is too long for a brew and too short for a roast.  Hmm…

    I honestly have very little clue, but 0-32 makes me think of the percentage of a coffee bean that is dissolvable solids, so I’m gonna go with inverse percentage of extraction over time of brew (ie how many dissolvable solids remain in the grounds over that long of a brew time)  

  18. Caramelisation of sugars during roasting?

  19. Peak extraction of soluble solids from ground coffee?

  20. The discharge of aroma components was coffee extracted in 90 seconds.

  21. Solubles yield as measured at various times during extraction?

  22. Seems to be about drip/pourover, and the Y-axis is either a measurement of the liquid dispensed or some weird percentage.  The X-axis is time, unless you want to confuse us even more :-)

  23. Moisture content of greenbeans during drying?

  24. Trailing 30 second average change (deg F/min) in bean pile temp over the course of a roast.

  25. Close enough! (The rate change is deg C/min – but I won’t argue it!) 

    Can you drop me an email with you address in it to jim @ the blog’s domain?

  26. not unless it’s taken from a cold thermometer (bad experimental method) in a room with an unstable temperature.

  27. Interesting. I’ve often thought about how amazingly useful it’d be to have this reading while roasting. Do you know of a device that can show  a numerical reading of the (x)s average rate rate of change throughout the roast. It’s something I’ve been meaning to research, but never got around to it.

  28. I see now! I would like to use this type of graph for RP120, if it is ok with you. It is a great way to show rate of temp change.

  29. Sorry if I misunderstand, this is then the inverse of an s-curve on a profile sheet? And then at about 9:30 it begins to rise again?

  30. I’ve been using live BT RoR graphing for about a year now. Looked familiar, forgot to factor the degrees C. Not sure how many roasters are graphing this but it sure gives a micro-look at a roast profile. With a more detailed graph you can even see the various amount of cracking highs and lows during 1st crack.

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